I own Gears of War for PC, but having to run the game using the disk is troublesome and also I want to play on-line with my brothers and can't because the game isn't in stock(cheap) on any major retailers.

I found out that the only Digital version of the game is on the Games for Windows Live marketplace, does anyone know how bad is it? What kind of DRM does game for windows live have? Is it too intrusive?

I have the GFWL marketplace GoW. IIRC, it has some variety of secure rom. I believe you are only allowed a limited number of installs per a month. Supposedly these installs are reset every month.

Aside from the DRM, you have a limited number of GFWL activations. How many, MS will not say (5-10 maybe). I've heard they will refund them once if you run out and ask tech support for more.

I've never played it online. The DRM was not noticeable.

Edit:
I haven't played it since ~2010.

Play it regularly, one of my favourite games of all time.

Basically you have to log into live when starting the game up to be able to play online. You can just use your MSN or Hotmail email address to do this. To log in when the game starts you press F11 and it brings an overlay down to log into your account.

You also have to log in to play single player, however you can just log in to a local account which can be created from the initial screen. Local account doesnt need email address, you just set it up so there is a profile there to save.

DRM on the disc version is literally having the disc in the drive when starting the game as it does a disc check and then registering the key on live on first startup. Marketplace version is fine also, nothing major there either, you just have to register the games key on live when you first start it up.

You don't need to run a client like steam/ origin. You log into GFWL from inside the game. The marketplace app is just for purchasing/ downloading (or it least it was last time I used it a 1.5 years ago)