Both Dirt 2 and Dirt Showdown offer playable demos on Steam. I'd suggest trying each to see which type of Dirt game you like better for openers.
It has been so long since I played demos, since I'm usually much more decisive which games I want or not.
So I did just that and downloaded the Dirt 2 demo. But whenever I hit play, nothing happens (other than those first time installs that executed, well, on the first time), the client just redirects me to the Dirt 2 store page. wth
Edit: apparently that's the "expected" behavior, according to some people, and that manually installing and logging into GfWL fixes the problem. All this hassle for a demo? Yeah, screw that.
I just saw your edit... unfortunately, I find that needs to be standard procedure with any GFWL title, namely that you need to download and install the current client before even installing or at least before attempting to run the GFWL game in question. Once you do that though in my experience it works just fine and actually does offer a nice matchmaking feature for multiplayer. Of course, it is yet one more login to remember...
I've recently been surprised to find GFWL has not been any trouble at all with three games I have installed but I did install the most current client beforehand based on past sour experience. I forgot to mention too, I needed to turn my firewall off temporarily to install the foolish thing but was then able to turn it back on and it worked fine. Gotta love how Microsoft's game software needs you to turn off Microsoft's firewall just to install. lol
Anyway, I found that stuff small potatoes once I understood how to deal with it and all is good now. I wouldn't let it keep you from enjoying a great game. Honestly, it is no big deal to install it one time. After that, set it to login automatically and you never need to use it/see it other than you'll see a little message it is logging in on game start and you'll get a nice matchmaking system in the game for multiplayer.
I am in a minority here but I don't mind it now that I know how to install the bugger.