Steam on distros other than Ubuntu (or a distro with similar package versions) sucks ass. I know they're working on the issue, but until then, Steam on Linux is completely useless to me.
What distros are you using? I've had no problems on Gentoo and have heard similar from Arch users. Sure it doesn't play nicely with the wider ecosystem (understatement), but it's been a long while since I could agree that Steam on Linux sucks.
The radeon drivers have actually been improving a lot. Their performance is fairly close to using the closed ones now, although, Catalyst does suck on Linux, but at least the open source ones are getting better.