Every version I've used since GoLive 5 has suffered from atrocious performance. 90 seconds to launch a simple site, 30 to open the bare application - what's it doing, translating all 69.5 megs of itself into Java? I've turned off all the bloatware bits (VersionCue in particular) and it still takes several seconds to open a 20-line file of static text with a bit of HTML formatting. The point-and-shoot tool takes a few seconds to respond to mouse movements, and you're never sure where it thinks it is when you release the mouse.

Sadly, I'm a bit locked into it as it used to work well and I designed a number of fairly complex sites with it. There are also a few things it does well, like SmartObjects, although they really only work in conjunction with other expen$ive Adobe products.