Good episode, but I wouldn't say great or original. Reminded me of Prometheus Unbound. And Sheppard falling for the oldest kiss trick in the book? Anyway, she was hot, and I hope we haven't seen the last of her. So overall it was good.
And now for a rant which I eluded to in the Sg1 vs Atlantis discussion: there's something about Atlantis that bugs me compared to Sg1. In Sg1, the group was a team and a family, and most episodes centered around them working together. Each of the members had a decent role in many episodes, and I really did think of them as an integrated team even only after the first or second season. Sure there were character-centric episodes, but overall I felt each member was special and important to the team and the show.
But in Atlantis, after already 3+ seasons, it feels that most episodes center on either Sheppard or McKay. I do like these two characters a lot, but I would like to see a more integrated team. Take a look at what Teyla has done in each episode in this season so far - not much at all. Neither has Ronon except for the one Ronon-centric episode. After this episode it doesn't seem that Carter will be a major character, though that remains to be seen. Everybody except Sheppard and McKay seem expendable - which, by the way, is at 4 characters by my count, maybe more.