Well, you can crack Gears but, there isn't much of a point. It won't "fix" anything, and the game works fine now anyway.
GFWL is easy to get setup - you just need a Live account. You can use your hotmail account info if you have one.
The software signs you in as the game starts.
Then on your first time playing the game you type in your serial key and you're good to go; play away.
You can play offline as well (I mean, without signing in, using an offline account), but I don't think it records your achievements that way, if that's important to you.
Use the home key, or the guide button on the 360 controller, to access the GFWL UI anytime.
People really just have a problem with GFWL because it's nowhere near as robust or feature rich as Steam, so it just looks funny in comparison.
Don't think of it as Steam and just let it do it's thing for 5-10 seconds as the game starts up, you won't think twice about it.
The only problem I have with Gears is that it forgets my Gamma setting every session. The game is kind of dark on my machine.
edit
Oh, I should mention. There is a problem with Windows 7 and 3 GFWL games, which need a pretty risky fix (involving System 32 files).
Viva Pinata, Halo 2, and that one multiplayer only game I can't think the name of ATM... shadow something or other... I don't know.
I found this out after getting Viva Pinata for 10 cents the other day on the Marketplace. It won't allow me to create an account so I can't save my progress. Kinda lame there.