OTOH, 8.9 was the first release where ETQW completely worked for me, and 8.10 works fine as well
You do know about the 3 concurrent fglrx development versions, right? Regressions shouldn't happen, but sometimes they do. If 8.8 works for you, the "next" version really would be 8.11, you just have to wait 3 months for it...
performance is about 50% of 8.8 and nothing works right when it comes to 3D.
Which card? Does glxinfo | grep direct say yes?
I haven't noticed any major regressions on my HD3850 AGP (yet), in fact the Unigine demos have got a good FPS boost with 8-10, maybe etqw aswell.
On the downside Tropics still dies after a while and mipmaps in compiz don't work.
Since 8-9 (I think) there is now a problem with the timedemos in the Quake 3 demo, where the fps randomly falls off alot with repeated runs.
Edit one thing to check if ETQW stops working is that seta r_useIndexBuffers is "1" in your ~/.etqw/base/etqwconfig.cfg