What do you plan to use it for? If you intend to play any games, the problem I see with the Grunt Ultra is that it doesn't seem to have a graphics card, even as an option. Integrated graphics are fine if all you're doing is stuff like schoolwork and web surfing, but they're no good for gaming.
If you go with that model, I recommend you pick up one of these:
https://pcpartpicker.com/product/mj4NnQ/zotac-video-card-zt7060510m It's not one of the big bad cards, and adds around a hundred bucks to the system price, but it's miles better than what comes standard with the Grunt.
Also note that, including the card I just linked you, you could build your own comparable machine for around $555.
Like so:
PCPartPicker part list /
Price breakdown by merchant
CPU: Intel Core i3-6100 3.7GHz Dual-Core Processor ($125.98 @ Newegg)
Motherboard: Gigabyte GA-H110M-A Micro ATX LGA1151 Motherboard ($45.99 @ Amazon)
Memory: G.Skill Aegis 8GB (2 x 4GB) DDR4-2133 Memory ($32.98 @ Newegg)
Storage: Western Digital Caviar Blue 1TB 3.5" 7200RPM Internal Hard Drive ($49.99 @ Amazon)
Video Card: Zotac GeForce GTX 750 Ti 2GB Video Card ($104.99 @ Newegg)
Case: Thermaltake Versa H21 Window ATX Mid Tower Case ($44.81 @ Amazon)
Power Supply: XFX TS 550W 80+ Bronze Certified ATX Power Supply ($63.99 @ Newegg)
Operating System: Microsoft Windows 10 Home OEM 64-bit ($85.95 @ Amazon)
Total: $554.68
Prices include shipping, taxes, and discounts when available
Generated by PCPartPicker 2016-06-19 00:29 EDT-0400
ETA: Found a little bit snazzier-looking case that costs slightly less than the Versa:
Raidmax Vortex
$40 more would get you a nice GTX 950 instead of the 750 Ti, and still cost less than the Grunt plus the other card.
If you're really nervous about putting a PC together yourself (which is totally understandable, though it really isn't that difficult,) before you decide what you want to do, I suggest you take a few days and look up some of the guides to building a PC here on Tom's forums and on YouTube. Newegg, among others, has put out a couple of series of really good step-by-step videos that show you the whole process from start to finish.