Interesting. I've been following this thread for ages and eventually bought the Crucial 960 GB SSD. I have experienced the same sleep behaviour from time to time. The computer simply doesn't go to sleep properly if the power cable is connected.
I thought it might be something to do with the apps SmartSleep or Chameleon SSD Optimizer, or some conflict between the two. Do you use either of these apps?
I had installed Chameleon on my first drive but never managed to use any of it's features. On this second drive that I have, no, I don't use either. Interesting that you have a sleep issue when plug into the AC when in my case it's entirely different, this exact problem, seem only to happen when I have had the MBP in sleep mode when running on the internal battery. Still hand't been able to reproduce when connected to the power outlet.