In general, I like few kinds of levels, which kind of levels that's quite open and technically not too difficult for replayability, and also one with gameplay gimmicks, with the setting on the outer space.
The example of the first one is Iridia from WipEout Pure. I know it's a racing game, but I like it because it's pretty open on the first half, but also offering a bit of technical turns that not too hard on the other half of the track.
The second one, however, I'll put the Aero Blasters/Air Buster here, because of the ice physics-like mechanics which makes the ship just glides as soon as you stops moving the ship itself. It starts on the Phase 4 up to about ¾ of Phase 5, and it's actually fun as soon as you get used to it. It's unique, and I really like it.