A minor improvement over the first one as it has a faster pace and more Dalek action with a story that feels more ambitious and cinematic, but since it is basically a children's movie it lacks the darkness suited for an invasion movie and it is hard to take serious. The TV show is so much better.
I'm not familiar with the series, so I can't really comment on how it holds up compared to the rest, but it's an energetic, campy sci-fi B-movie. Peter Cushing is adequate as the doctor, though he's given surprisingly little screen time. The cheesy special effects only seem to add to its charm. Great score by Bill McGuffie.
Interesting in that it's kind of close to the TV series, but not exactly, and done much more opulently than the original. It would be as if a movie of one of those Chinese Harry Potter ripoff books was done with 10 times the money of the authorized Hollywood versions.