Well, I do have my gripes with the P180 (I can't move the mobo standoffs? what?!) but the fact that I can pull the HD bays, have drive rails, 120 mm fans, a seperated PSU area (which is a little too cramped...even for normal sized antec PSUs!) and all the rubber grommets for mounting stuff....from my CM Praetorian, the P180 is a HUGE improvement...I miss the mobo tray, but the P180 is quite speacious, so it isn't needed as badly...and that plastic shroud is too bulky...it gets in the way of cables, and doesn't seem to have an effect...but I still love it. For $100, it was a VERY good buy.
Like I said, the removable filters are a very good +, and CM never understood how to use a good filter...instead the put in a small metal mesh that really restricts air, and then add foam that you cannot remove to wash, that FURTHER restricts air...I won't be buying any CM cases again until they learn a few engineering ideas...