I can't explain why, but this episode felt distinctly average to me even though a lot of cool stuff happened. The story in 2007 wasn't all that good and the story in 1977 was good and had some very good scenes but it just didn't feel all that compelling. It is right on the border of Above Average but it didn't quite make it. Normally I finish the episode and come right here to post about it, but this week I actually forgot and started posting in other forums instead.
Enjoyable to watch, but it was just pleasant and nothing more in my opinion. I can certainly understand why others think it is Excellent.