I have never once had a problem with it.
Then you sir and a less than handful are the only ones who have NEVER had a problem using Steam.(Ask Stant about his use of Steam and their are others out there.)
I myself can't get aboard because to me it's like asking permission to play a game I PAID for. When it comes to original Sins or any of the X-space games, I just fire it up. No middle man, one day I may break down and use Steam, but not right now...