Atlantis was definately it's own show. It didn't try stealing from sg-1 or anything. I like the fact that they got away from the religious aspects of the enemy race. The wraith are probably my favorite alien race. Diferent enough to say they didn't just throw on a wig, yet human enough where they weren't bizzar to look at like those aliens on Universe. There explanation was pretty alright too. I don't think they had enough reacuring wraiths. Don't get me wrong, Tod is one of my favorite bad guys of all the SG series. But they still could have had another. I didn't like the Genii as a reacuuring race.
Back to the more general plot. It was nice bringing the eighth chevron into play. There were a number of good stories. The characters/actors were alright. I liked Ronan well eough but he was a bit flat and underdeveloped. I get that was kind of the way he was supposed to be, but he could have offered a bit more. Then there's Tayla. The Teal'c or Mr. Spock of the series as it were. Just a lot more boring. I know every show has to have that "spiritual" character, but she was just rediculous. Of coarse, I'm a little biased of sorts. I hate pretty much all female characters in all movies and shows. Don't think I'm sexist, I'm a female myself, but male characters just tend to be better. The show really didn't have that impact that sg-1 did. There wasn't that underlying progression in story or technology. Also, the threat to Earth didn't come across as so iminant.
In the end, I truly enjoyed the show. Infact, I had a twenty minute rant with my living room wall after finnishing the last episode and realizing the movie never aired.