I really think this episode is "SG-1" at its very best. It was simply brilliant. A nice, old-fashioned episode that allows "SG-1" to get back to its roots in many ways.
This episode acts as a sequel to several of Season Eight's best, particularly "Full Alert" and "Reckoning Part 2". Fortunately, it emulates the greatness of these two episodes. I especially love the whole "Goa'uld on Earth" storyline. Admittedly, it's something that they've explored quite a few times before but it is done in a manner that keeps its interesting here.
It was great to get the band back together, as Mitchell put it. For the first six episodes of the season, all I was thinking was "When is SG-1 getting back together?!" It was long overdue. This is one of the things that, for me, made to seem like an old fashioned episode. It was great to see Daniel, Sam and Teal'c working together in the normal way for the first time since late last season. It was nice to get a brief respite from the whole Ori storyline. In fact, I think this is the best episode of the season so far partly for that reason. It hasn't really grabbed me yet.
The concept of four different Baals on Earth and possibly dozens throughout the galaxy is extremely scary. One was creepy enough. And that one is still out there hiding somewhere, probably trying to rebuild his power base and likely planning numerous attacks.