If you've already installed it via gfwl, going over to the steam version is a piece of cake. All you do is get the basic version on steam and when you launch it all your stuff is there. Then you can uninstall your gfwl version. Really no catch.

Regarding multiplayer, are those running from the steam-interface playing in separate game rooms from those using the original gfwl version?

 

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Regarding multiplayer, are those running from the steam-interface playing in separate game rooms from those using the original gfwl version?

 

No, all online is still handled via GFWL.

The valve boys must be home from Hawaii. I got my forum approval today.

Same here, I got my approval yesterday afternoon. I signed up for the forums last Thursday morning.