Sarah Jane "really" is a kids show.
I get kind of annoyed by some of the "fillerish" episodes, especially in S5. We didn't really need a two-parter about dinosaurs in S5. And the S3 episode about the stone angels was way better than the S5 one. But the arc episodes in S5 were awesome. Bad Wolf is the only comparable arc (and BW might relate to the paradoxes in S5).
On the other hand, some of the fillerish stuff is great. I really liked the episode that introduced Dr. Sung, for example. The first stone angels was really good. The Ood episodes are cool.