I agree with what some people said of the episode: it is your standard "Monster of the Week" type of episode, but compared to the goofiness and experimental nature of Season 6, I'll take what we've gotten so far with Season 7 anyday. I don't know why people would think this is a bad season. Maybe the myth-arc will be bad, but so far, the actual stand-alone episodes are fantastic.
This episode was probably my least favorite of the three that have aired so far after the season premiere, but it was definitely entertaining. We have some good Scully/Mulder banter, an interesting case and a set of teenagers who have found something that is truly crazy. The scenes where we see what their super-speed can do is superbly done.
As usual, we don't get much in the way of an explanation, but when an episode like this is doing so much right, one shouldn't try to nitpick or complain too much. The episode moved at just the right pace and made me care about these characters, even if some of them were horrible people and some of them weren't built up so much.