Some of them are really well done and realistic.
I love the way Bratac and Ronon, and Col. Dillon Everett (the Atlantis marine boss in The Siege) look, they're the most convincing. And McKay has his face, but I think the hair sort of makes him look weird. 
Thanks, yep the results vary as the faces are rendered from photographs and thus quality depends on the input. I can't create hair so I'm using the template/Marian Quandt hair and edit it.
Now, to get around the problem of the hair I had a quick plan: Cover the hair with a helmet/cap/woolie
While this works for the Stargate SG-1 characters where I've seen headgear, in Atlantis I've yet to see any major character to think of protecting his most vulnerable body part, only exception being Ford, who wears atleast a blue cap like all the time.
I guess helmets were not part of the inventory.