I have a 902 and can tell you that the 1200 is massive. You need to make a list of needs versus desires.
Do you need pretty lights?
Do you need to have a five to eight HD raid array?
Are you going to be running a three or four card crossfire/SLI setup?
Do you want to lug around a 45 pound case? (BTW, that is BEFORE you put gear in it!)
I am not trying to turn you off the decision, but people often see a nice case on newegg and impulse buy and regret it later. The twelve hundred is nothing like tool-less and the multiple filters require regular once a month cleaning. If you have pets, more often. The case is steel and very heavy, but that also means that your components will be well protected. The top fan move a large amount of air, but it can be loud at high settings. Cable management is not a breeze, it requires effort and forethought in the 1200, but can be done. Once your hard drives are in it takes a fairly major operation to remove them, so don’t put used drives in, or drives that you ever want to remove.
If all that doesn’t scare you off, dive in. It’s a beautiful case, not for the faint hearted.
A sabertooth will fit without issue.