Every 10.x.0 release has been like this. And as I've said, I've had no major issues in my Clean Install yet.
Well, I am a Apple user from OS9 and wend all the way to OS X 10.7GM.
Honestly, together with OS X 10.0 and 10.2, Lion is the worst OS X version ever.
As a developer for OS X for about 6 years now I can also mention that programming for the new APIs is sometimes a hell. You really have to do pull out some tricks to bypass bugs for Lion (read: to keep performance on a good level).
I am going to say it again: not all people see the difference between a 30fps and 60fps shooter.
On my new Macbook Pro 17 i7 with Intel 3000HD the overall GUI performance is not on par with SL. Jerky graphic animations are things I find very annoying. (and yes, I am very picky on this)
Also, Quartz Debug (included in the Xcode package) shows it IS a lot slower.
In the end it all depends how picky the user will be. If he don't mind using a lesser smooth GUI then Lion will be ok for those.
For me, unfortunality it isn't.