It's a nice feature as long as they don't force you to update.
I had an issue with World of Warcraft using 10.8 so I downgraded to 10.7. It'd suck if Steam kept trying to update me when I didn't want it.
Strangely, I didn't have to reboot after installing 10.9 from Steam. I'm guessing the normal install would work the same way, but I must not have realized it.

As long as it is optional, its good. This is a win situation for Steam.

+1 ;-)

LOL. Nice. :)

Waiting for the day when Valve buys GoG from CD Projekt and everyone here commits e-seppuku. Ahem, jokes aside, to the topic... I generally don't like anything automatically updated for me. That said, there is an option to disable it.

Thanks . . . =)