I think they are very different.
Is it just me, or are these pretty similar? When we went in 2012, we weren't able to do TSMM, but we did ride Buzz on our last day. I was "eh" about it, but I know so many people rave about TSMM. Are they all that different?
TSMM is more advanced in terms of technology - and I think more fun. 
They both have a video game quality in them, and they are fully interactive experiences. TSMM is more inmersive and simply better imo. Personally I feel like Buzz is kind of difficult to play because you can barely see the laser (at least in my experience). The 3D also adds a lot to the experience.
It is, which is really fun.I felt the same way, but from what I've read, TSMM is in 3D!
from what I've read, TSMM is in 3D!
Is it just me, or are these pretty similar? When we went in 2012, we weren't able to do TSMM, but we did ride Buzz on our last day. I was "eh" about it, but I know so many people rave about TSMM. Are they all that different?