I have to agree with Tom about the 800D being an oven. I have one with six months now and I had to add a 120MM high CFM fan on the roof of the case to get the heat out of the case. Only until Tom said that it was an oven about two months ago I didnt realise how poor the fans were thant came with the case were.
I was gaming that day and my GTX280 was getting fair hot so I pulled off the side panel of the case and the internals of the case was very hot. The hot air hit me when I pulled the side panel off. I have a Corsair H50 with two fans on it pushing the air into the case also. I also had to replace the 140MM rear fan with a 120MM fan for the H50 so I used some cable ties to mount the 140MM fan on the roof of the case to help remove the heat from the case. The fans that came with the case are very quiet @ 100% but they are very low CFM fans too so they dont help move the air much.
Not only that but those plastic covers inside the case rattle a lot (I removed the cover over the HDD fan cause it rattled with the HDDs vibration) and the plastic blank 5 1/4" covers are loose so they rattle a little with the HDD vibration and I had to put foam under the feet of the case because there is no dampening for the HDD's so my computer desk was humming at me when the computer was running.
I love the size of my 800D and the front hot swap bay , but I think I will be changing the case for something better built as soon as I can. I had an Antec P190 and changed it because it was too small inside the motherboard area but it was better at cooling and the HDD's didnt make my desk hummmmmmmm at me. I will be looking out for a big case that is some bit decent (Better than my 800D) with good cooling , lots of internal space (like my 800D) and has HDD dampening. The 600T is a little bit too small for me though. I want a bigger case than that.
Fractal Design Define R4 - Core I5 6600K
MSI GTX980 (Stock cooler) - Asus Z170-P D3
16GB Kingston HyperX 1866 - Corsair HX1000
BENQ XL2411Z - Asus Xonar D2 - Logitech Z906