Portal 2 Linux Beta working perfectly for me on ZorinOS 8 Core (64bit)
I am running Portal 2 [beta] on Zorin OS 8 Core 64bit and it runs flawlessly on max settings (i7 3770k with a GTX 670 using 304 proprietary drivers from repos). I didn't have one "weird linuxy thing" and it was just a blast. Looking forward to release as well as CS:GO whenever that comes around :)
Thanks and great job Valve!
As a side note, I have found Zorin OS to be a fantastic operating system for Linux newbies like myself. I have learned a ton and I feel alot more confident using more complicated distros now. Since it is based on Ubuntu, it is very compatible with Steam.