All of the store bought games I have with steamworks have installed from the disk (though DoW2 did need reminding to). They then patched from the net.
It uses neglagble ram and processor power. And in return it does most of the tedious bits of gaming for me.
I'd like the option to install accross multiple drives, but thats a minor niggle.
The reason for steam exsclusives is that if you want to use steam matchmaking you have to have the rest of steam, this means that all versions have to have all aspects of steam. This means that disc copies have it, and no other online opperators will carry it. It should be noted that steam would prefer to sell you DLC in steam, buts fine with you using your own store if you want, hell they even allow the travesty that is GFWL, a system that offers the following; DLC, larger expansion packs, full games, community and matchmaking functions, achievements and DRM. In otherwords steam is quite happy to sell its competiters services becasue its confident it's aer better.
