I don't particularly see a performance issue as far as TM slowing down or something of the sort when this happens, I really only noticed this because any new file I'd open wouldnt have syntax highlighting, and fans would go crazy after a little while on this. At first wasn't sure what was causing this, then I figured out that opening any minified js file or a long js file would cause this. Instantly highlighting stops for all other files and TM process goes over 100%. Only way to stop is force quitting.
It is slower than v1 indeed, I'm on OS X 10.7 4Gb ram. Other than this I have no problems really with TM2, but it feels overall slower (also noticable when you have many files open)
Same here, other than that TM2 has been quite pleasant to work on.