I'm somewhat disappointed by this episode, mainly because I didn't want the penultimate to be another filler episode - in this case a CSI alternate reality. If it happened earlier in the season, I would probably thought better of it. I wonder if there was enough time to change the script of this episode after the cancellation notice.
As far as the story, I think they tried too hard to make it CSI. I'm just an occasional watcher of CSI, and maybe others who love CSI enjoyed the episode because of it. The problem for me is that this is Atlantis, and the only mystery was figuring out whether this was an alternate reality or a dream until about halfway through. At least Todd and Walter were there. It's too bad Ronon wasn't there to show off his blaster! How did the wraith hive get to Earth? Did that Todd have all the information necessary? If so, how do they know that other wraith (under Todd) in the Pegasus Galaxy don't already know Earth's location?
Anyway, a disappointing penultimate episode, and I'm looking forward to the finale.