At least in large part mode. Using the punch holder model, I am getting the exact same rebuild times as I did with SW 2009. I think most of their speed efforts went into large assembly.
Still, I am getting into 2010. A lot of good improvements have been made
Large assembly work in SW2010 seems a little slower than it's predecessor. Not sure about the how and why's but have already asked our VAR to look into the issue. Alterations to mate distances for example take 20-30 seconds to update. Productivity has really taken a beating.
I have found that the first few weeks after upgrading to major releases do bring on such issues. Things tend to calm down once all files have been fully converted to the version.
The productivity enhancements that were promoted with the product have delivered nicely though I must add. Additional functionality with multi-body parts are already paying divdends for us.