A decent entry in the 007 franchise. Not quite as crazy as Goldfinger, but still daft and silly enough to be enjoyable. The main problem with Thunderball is that it crosses the 120-minute barrier, which is a bit excessive for a simple film like this. Some tighter editing would've done this film a lot of good.
Connery is a decent Bond. Not too serious, but no goof either. The rest of the cast isn't quite up to par I'm afraid. The bad guy is pretty lame and the Bond girl clearly wasn't chosen for her acting skills. Add a low quality plot which is a little too prevalent and get you get a film that struggles where it shouldn't.
At least the action is fun and there's still plenty of silliness. The many scenes with the sharks stand out, but the finale is also pretty hilarious. It makes for decent entertainment, but it should've lost at least 30 minutes. Not good enough to be consistently fun, hopefully the next films manage to trim some of that excess fat.