Personally I prefer the CoolerMaster, nothing more than a personal preference though. I have looked into getting a ThermalTake case several times, and I just don't like them, they are great cases, mainly I just don't like the CD drives being shut behind a door (I had several cases were the push to open doors, breaks, and then won't stay closed.).
They are both great cases, I would just get the on that you like the looks of best. They are both from reputable, known manufacturers, and should serve you well, no matter which one you get. Both these cases are known for performance, so they really are "sort of" "equals."