I posted this on someone else's question about cases, but I'll post it here, too:
The TT Armor has pointless metal flaps on the front, but is one of my favorite cases because you can easily fit a customized water cooling loop inside and mount a radiator on the bottom with minimal modification. The Stacker 830 is arguably as good, I just don't like how it looks.
A good friend of mine has the 900. It is smaller than the Armor and looks a little slicker, but don't plan on running anything in SLI or Crossfire without taking out that side fan. Also, newer cards like the 8800GTX or GT or 3800 series will leave the inside of the case with little room to spare.
So, if you want plenty of room to work with and upgraded cooling (air or water), go with the armor. If all stock, I recommend the 900; you can fit decent after market cooling in this case, though.
Both cases are sturdily built. Replace the 120mm fans with some good Yate Loon D12SL-12 fans if you want fans that are actually quiet and push some decent air. I'd also recommend a fan controller.
The coolermaster stacker cases are always a good choice, but I personally don't like the way they look.
Might I suggest this? I have it, my father has two and a friend bought it. I did end up buying another fan and putting it in the second front mount. Very quiet for as many fans. I run a Q6600, 8800GTX, OCZ 750W PSU, 80GB and 250GB SATA drives and a V1 cooler (big V shaped thingy).
I have the Thermaltake Armor Series VA8003BWS. I don't have the Antec case so I am not trying to compare the two.
I run my system with seven hard drives (picked up a second drive bay), two optical drives, and a single 8800GTX video card. I also have a PCI sound card and a 3ware 9650 hardware RAID6 card. The case does a good job of cooling all this hardware and providing sufficient space for all the drives and for routing the cables around. It's still a bit of a mess inside but hey, my RAID6 card has eight SATA cables to deal with. Oh, and I have the Scythe Ninja CPU cooler. Anyway, my point is that the case is sufficiently large enough for this.
If you are looking at only a couple of optical drives, a single hard drive, and perhaps one or two 8800GT video cards, it's probably overkill. But I would most certainly buy this case again and would recommend it to others. It's nice to have room to grow.
And yes, the 'fin' things on the front of the case are a bit silly. Still, they are easily pushed open when a CD ejects from the drive so it's not really a big deal.
I really like the p180, especially with the separate chamber for the power supply. My current case has the 120 fan from ps blowing warm air onto the mobo, the trend seems to be going to these power supplies with the 120 exhaust fans. Had I known where the hot air was going, I would have gotten something else.
I wish more case manufacturers were building cases to accommodate this trend. I would like to see Antec come out with a revision on the 900 with the separate chamber, for those of us that like a little more bling with our gaming boxes.
Also with the p180 or other cases with bottom mounting power supply, wouldn't it make sense to have perforations in the bottom of the case to blow (120) PS heat directly out of the case? The one thing I don't like about the Antec 900 is with my current power supply, it would be blowing heat right at the video cards! Like they aren't hot enough..
The P180 is really nice. However, as I post elsewhere, if you plan to run SLI with 8800 ultras, you will encounter problems because the power cables from the psu have to snake through a tiny hole between compartments which could interfere with the placement/operation of the 2nd gpu, depending of course on which mobo you use.
I've got on Armor on the floor next to me as I type this, and I really like it a lot. It's big and open on the inside, which makes it really easy to work in (especially for a ham-handed klutz like me). The doors....I dunno, they're not real useful, but I think they look cool, and they're magnetic enough where they don't swing wildly. In comparison, my buddy has one of the 900's, and that looks pretty nice too. I feel like the Armor is quieter, but I don't really have any evidence to back that up. It's really all personal preference, but I'd recommend the Armor to just about anyone (assuming you have room for it.....it's sorta huge).