Opposite experience for me. 2005 and 2008 were incredibly slow, painful, and prone to locking up or flat out crashing. I don't think I've had one lock up or crash since I switched over to 2010 about 4 or 5 months ago. Also, I can have multiple instances of it open now without my whole computer gasping for RAM. In fact, when I launch a second instance it comes up in a split second, making me feel like the core parts are sharing common resources.