Haven't bought from them before, but a friend bought Brink from them a few months back and hasn't had any issues. Said it took them roughly 3 hours to send him a scanned copy of the key.
The Space Marine product page does say that this is the key for a digital copy though, so don't expect a scanned copy.
EDIT: They're currently out of stock.
Probably when more people start asking nonsensical question like this.
I can't say anything if this is cheap, but just want to say that I really liked the single player campaign of this game. It's a bit repetitive but that's not necessarily a bad thing.
The game is not designed for multiplayer, though that mode is available if you want to get more value out of it.
Anyone know the source of the keys? Ruski or Thai/Viet??
When will these sites start taking a scanned copy of a $20 note as payment?