Cooler Master is redefining the high-end case segment once more. This is certainly no easy task, as this case is supposed to follow up on the very successful Stacker series. The lack of a motherboard tray or lack of BTX support are no big deal and Cooler Master has done well, not trying to include these. Instead the Cosmos is so large, that inserting a mainboard is a breeze and the BTX crowd is rather small when compared to the widely available ATX and even E-ATX user base. The new features certainly outweigh the left out ones. The padded side panels, thin foam linings for the PSU and the hard drive drawers all shout "silence" and this is what the Cosmos is made for - absolute silence.
Just turn down the four included 120 mm fans or replace the top two with even slower 140 mm variants and you should be able to sleep next to your high-system without any problems. The push to secure and release any installed 5.25 inch devices is the best screwless implementation I have ever seen and really works incredibly well. Cooler Master has made the Cosmos larger and heavier, due to the use of steel, which does not really make this chassis one to take to a LAN party, but it looks great under any desk.