Is this a good Desktop PC for the money ?

A prebuilt... yuck
And they even have the guts to act as if that was a good deal.

Just build it yourself, save cash and end up with something that's better in every way.

PCPartPicker part list / Price breakdown by merchant

CPU: AMD - Ryzen 7 2700X 3.7GHz 8-Core Processor ($309.99 @ SuperBiiz)
Motherboard: ASRock - X470 Master SLI/AC ATX AM4 Motherboard ($129.99 @ Newegg)
Memory: G.Skill - Ripjaws V Series 16GB (2 x 8GB) DDR4-3000 Memory ($154.99 @ Newegg)
Storage: Crucial - MX500 250GB M.2-2280 Solid State Drive ($69.85 @ OutletPC)
Storage: Seagate - Barracuda 2TB 3.5" 7200RPM Internal Hard Drive ($58.89 @ OutletPC)
Video Card: EVGA - GeForce GTX 1070 8GB SC GAMING ACX 3.0 Black Edition Video Card ($399.99 @ Amazon)
Case: NZXT - S340 (Black/Red) ATX Mid Tower Case ($49.99 @ SuperBiiz)
Power Supply: EVGA - SuperNOVA G2 650W 80+ Gold Certified Fully-Modular ATX Power Supply ($69.99 @ B&H)
Operating System: Microsoft - Windows 10 Home OEM 64-bit ($89.89 @ OutletPC)
Total: $1333.57
Prices include shipping, taxes, and discounts when available
Generated by PCPartPicker 2018-07-15 19:23 EDT-0400

1. The Dell build is running off a 1070. The Intel build above has a 1070Ti, even if the FPS gain is 10 to 15 FPS more, it is still a gain.

2. That Dell build is most likely running an 8700k on a locked motherboard for that price. Dell has done this many times before. Unless they mention "overclockable processors" or something to that extent, the motherboard is most likely a B360 or H310 or H370 with no room for overclocking.

3. I will give it to them, storage is a good aspect. Has an M.2 drive and 2 TB HDD, bit better than what we have above.

4. The cooler used for the chip is most likely a stock cooler which can't handle the 8700k, which is known to run hot.

5. Pre-builts are notorious for running off poor PSU's. At that price point, Dell has most likely put a shoddy PSU in. Tomshardware is full of threads of people with prebuilts of supposedly good value but PSU's are horrible.

Otherwise, specs are okay. But at that price point, I would not go pre-built at all.

You have a point. If OP already has a system, might be not a bad idea to change it a bit.

@OP:
The only reason I gave that build is for sheer power. You can have a build with a slower processor but better GPU too. And for a cheaper price.

Here:
Intel -
Non - Overclockable:
PCPartPicker part list / Price breakdown by merchant

CPU: Intel - Core i5-8400 2.8GHz 6-Core Processor ($178.89 @ OutletPC)
Motherboard: ASRock - Z370 Extreme4 ATX LGA1151 Motherboard ($112.00 @ Newegg)
Memory: G.Skill - Ripjaws V Series 16GB (2 x 8GB) DDR4-3000 Memory ($154.99 @ Newegg)
Storage: ADATA - Ultimate SU800 256GB 2.5" Solid State Drive ($54.99 @ Newegg Marketplace)
Storage: Seagate - Barracuda 2TB 3.5" 7200RPM Internal Hard Drive ($58.89 @ OutletPC)
Video Card: MSI - GeForce GTX 1080 8GB DUKE OC Video Card ($494.99 @ B&H)
Case: NZXT - S340 (Black/Red) ATX Mid Tower Case ($49.99 @ SuperBiiz)
Power Supply: EVGA - SuperNOVA G3 550W 80+ Gold Certified Fully-Modular ATX Power Supply ($47.99 @ Newegg)
Operating System: Microsoft - Windows 10 Home OEM 64-bit ($89.89 @ OutletPC)
Total: $1242.62
Prices include shipping, taxes, and discounts when available
Generated by PCPartPicker 2018-07-15 22:20 EDT-0400

Overclockable:
PCPartPicker part list / Price breakdown by merchant

CPU: Intel - Core i5-8600K 3.6GHz 6-Core Processor ($238.99 @ Amazon)
CPU Cooler: CRYORIG - H7 49.0 CFM CPU Cooler ($27.99 @ Newegg Marketplace)
Motherboard: ASRock - Z370 Extreme4 ATX LGA1151 Motherboard ($112.00 @ Newegg)
Memory: G.Skill - Ripjaws V Series 16GB (2 x 8GB) DDR4-3000 Memory ($154.99 @ Newegg)
Storage: ADATA - Ultimate SU800 256GB 2.5" Solid State Drive ($54.99 @ Newegg Marketplace)
Storage: Western Digital - Caviar Blue 1TB 3.5" 7200RPM Internal Hard Drive ($43.90 @ OutletPC)
Video Card: MSI - GeForce GTX 1080 8GB DUKE OC Video Card ($494.99 @ B&H)
Case: NZXT - S340 (Black/Red) ATX Mid Tower Case ($49.99 @ SuperBiiz)
Power Supply: EVGA - SuperNOVA G3 550W 80+ Gold Certified Fully-Modular ATX Power Supply ($47.99 @ Newegg)
Operating System: Microsoft - Windows 10 Home OEM 64-bit ($89.89 @ OutletPC)
Total: $1315.72
Prices include shipping, taxes, and discounts when available
Generated by PCPartPicker 2018-07-15 22:21 EDT-0400

Ryzen:
Ryzen 5 2600:
PCPartPicker part list / Price breakdown by merchant

CPU: AMD - Ryzen 5 2600 3.4GHz 6-Core Processor ($169.99 @ Amazon)
Motherboard: MSI - X470 GAMING PLUS ATX AM4 Motherboard ($129.99 @ B&H)
Memory: G.Skill - Ripjaws V Series 16GB (2 x 8GB) DDR4-3000 Memory ($154.99 @ Newegg)
Storage: ADATA - Ultimate SU800 256GB 2.5" Solid State Drive ($54.99 @ Newegg Marketplace)
Storage: Western Digital - Caviar Blue 1TB 3.5" 7200RPM Internal Hard Drive ($43.90 @ OutletPC)
Video Card: MSI - GeForce GTX 1080 8GB DUKE OC Video Card ($494.99 @ B&H)
Case: NZXT - S340 (Black/Red) ATX Mid Tower Case ($49.99 @ SuperBiiz)
Power Supply: EVGA - SuperNOVA G3 550W 80+ Gold Certified Fully-Modular ATX Power Supply ($47.99 @ Newegg)
Operating System: Microsoft - Windows 10 Home OEM 64-bit ($89.89 @ OutletPC)
Total: $1236.72
Prices include shipping, taxes, and discounts when available
Generated by PCPartPicker 2018-07-15 22:27 EDT-0400

Ryzen 5 2600x:
PCPartPicker part list / Price breakdown by merchant

CPU: AMD - Ryzen 5 2600X 3.6GHz 6-Core Processor ($222.89 @ B&H)
Motherboard: MSI - X470 GAMING PLUS ATX AM4 Motherboard ($129.99 @ B&H)
Memory: G.Skill - Ripjaws V Series 16GB (2 x 8GB) DDR4-3000 Memory ($154.99 @ Newegg)
Storage: ADATA - Ultimate SU800 256GB 2.5" Solid State Drive ($54.99 @ Newegg Marketplace)
Storage: Western Digital - Caviar Blue 1TB 3.5" 7200RPM Internal Hard Drive ($43.90 @ OutletPC)
Video Card: MSI - GeForce GTX 1080 8GB DUKE OC Video Card ($494.99 @ B&H)
Case: NZXT - S340 (Black/Red) ATX Mid Tower Case ($49.99 @ SuperBiiz)
Power Supply: EVGA - SuperNOVA G3 550W 80+ Gold Certified Fully-Modular ATX Power Supply ($47.99 @ Newegg)
Operating System: Microsoft - Windows 10 Home OEM 64-bit ($89.89 @ OutletPC)
Total: $1289.62
Prices include shipping, taxes, and discounts when available
Generated by PCPartPicker 2018-07-15 22:28 EDT-0400

Really, the Ryzen 5 2600 can be overclocked to match the 2600x.

All builds have the same specs as the Intel build previously posted but with a GTX 1080.

Price and performance-wise, I'd say that's actually a pretty decent system for 1080p gaming. It would likely cost you close to $1300 to put together a system yourself with the exact same specs, so you would only be saving $100 or so by doing that.

I don't think you actually even need an i7-8700K though. There's no real reason to go with an 8700K when not overclocking, since the i7-8700 (non-k) has almost identical boost clocks and offers nearly identical performance to the 8700k at a lower price. Or even the i5-8400 would likely be a good option for gaming and those other tasks at a much lower price still.

As for the Ryzen 2700X, it might have 8 cores with SMT instead of 6 like the 8700 or 8700K, but each of the 8700's cores are a bit faster, and for your needs that will likely be a bit more beneficial to performance. Of course, again, something like a Ryzen 2600X could be a decent option at a lower price as well.

One thing I'm wondering though is what your current system's specs are. Aside from adding more cores at a given price point (which are not even utilized by most software yet), Intel's CPUs haven't actually increased in performance by a whole lot over the last 5 years. If your existing system has an i5 or better processor, it's possible that you might be able to see a big performance improvement just by upgrading certain components, such as getting a new graphics card and an SSD, at a much lower cost. One nice thing about PCs is that they can typically be upgraded without replacing the whole system.

3770 is still a great chip. If you want to save costs, stick with it and upgrade RAM to 16 gigs and change everything else.

However, it does have its age, so if you are changing everything, might as well change the CPU as well.

In the past 5 years or so, there really has not been much change in terms of FPS from with each iteration of Intel chip released so keep that in mind.

As for your question of how to build:

How to Build:
https://www.youtube.com/watch?v=IhX0fOUYd8Q

What to do after:
https://www.youtube.com/watch?v=LbpqkiaO7q4
https://www.youtube.com/watch?v=xURz-SSQUVY

I agree that the i7-3770 is still decent enough CPU. The new CPUs will be a bit faster, but it's not exactly a night and day difference. As far as games are concerned, you could see a huge performance improvement from just a graphics card upgrade. The HD 7700-series cards are pretty dated this point, and something like a GTX 1070 should be at least several times as fast, and would allow you to run current games at their highest settings at 1080p resolution. A graphics card upgrade is usually pretty easy, and is most likely something you could do yourself. You would want to check what power supply you have though to make sure it has the capacity to support the newer card. Especially if it was a pre-built system, many manufacturers often won't include a better power supply than is needed for the hardware that the system ships with. The power supply is the metal box inside the computer that has all the power cords running to it, and it usually has its model number and maximum wattage listed on the side.

As far as RAM goes, 12GB is still good, and most games and applications can even get along fine on just 8GB still. If your system doesn't feel as responsive as you would like, installing Windows and your applications to an SSD drive would likely help a lot if they are currently on a regular hard drive. SSDs tend to be a lot faster and more responsive than traditional drives. You could still keep your existing hard drive for additional storage though, since your bulk data files probably don't need that kind of performance. Reinstalling Windows and your programs to an SSD can be a bit more involved than installing a video card, but it's not exactly super complex or anything. The size of the SSD will depend on what you want to store on there. If it's just Windows, your applications and a few games, then somewhere around 250GB would probably be fine, but if you want to install more games on there, you might want to look for an SSD around 500GB or so.

Of course, getting a new computer is another option, and it could perform a bit better still, but most of those performance gains could be had with just some hardware upgrades at a much lower cost. A GTX 1070 and an SSD with around 500GB capacity could be bought for less than $600.

What specs did you get? Most likely a rip-off. For $1500 you can get some good stuff.