I created a Warhammer 40k Space Marines Logitech G13 profile because the default one that you find is less than useless. I started playing Warhammer 40k Space Marines again when I saw that Steam had a badge for it, and I found a multiplayer game.
It turns out that if you select Versus, then Seize Ground and then select Dreadnought Assault, you can find a single server on the Internet to play on. I would still not recommend buying this game unless you want to play the campaign, which is fun, but only about 5 or 6 hours of game place.
The profile will get you killed a lot in multiplayer. Below are the keyboard and mouse layout images for the profile because it is different from most first-person shooters.