Not exactly sure what you mean here, but you have to install Steam even if you buy the DVD. All installs are the same, as it says in the FAQ.
But I think I'll do as you and get the DVD. It's good to have something physical.

EDIT: And I also do believe that there is a lock on Steam that prevents you from playing until it has actually been released. That goes for the DVD as well obviously, since you need Steam to install.
Just talking about where you buy it from:
$60 steam: early unlock
$60 Amazon: game box/map/ cd/ arrives 11/11/11 ussualy morning and just play.
about the steam use, doesn't matter, pricing does. So in other words lose items for a few hours earlier of play for more $$ at the end. Not a good deal to me, just for the impatient one.
If steam wasnt such a money hungry mofo and woudl just sell the boxes and let people early "preload" and play release date from the account now that would be nice! CD-less boxes I could care a crap, but give me something physical!
Maybe I'm too old school and don't aprove of this digital copy crap. I did it for two worlds and regret it.
edit: meant two worlds 2, oh yeah and I'm trying to tell myself you want a PHYSICAL MAP not a digital map untop of the digital map in game lol.... =/