On GFWL, you have to download the game, then do an install... on steam you download the game, and you don't need to install anything, it's already extracted and setup ready to run... how does it wourk on D2D?
I have a lot of games which I purchased from D2D. You can download each game's installer from your account page directly; using their client is optional. Actually, when you place your order you get a download link to click to immediately download the installer.
I picked up Bully:SE last night and found that there's a patch available for it (below). I haven't installed the game yet, so I'm unsure if D2D offers the patched game or not already:
28 Apr Bully PC Patch 1.200 released!
Published April 28th, 2009 at 11:39 AM PST | Posted by AJ Collins | Added to Bully: Scholarship Edition »
A while back, we reported that Bully had a few problems to do with lots of memory on 64-bit versions of Windows and suggested a temporary fix for it. Well today Rockstar has released patch 1.200 for Bully. The patch address this issue, improves the streaming for objects, and fixes random crashes and lock ups. If you have the game from Steam, it should update automatically. However, retail owners will have to download an updater file. Download the patch from the links below for your region.
Download: English, French, Italian, German, Spanish