I totally did not see this revealer coming, which is the sign of an excellent collection of theme answers, right? In this case, each of the four has a different spin on spinning, thus leading to SPINCLASS, which is in fact a fifth example of spinning. My head is spinning. I like that the four examples are so different in contemporaneity as well, from MINNESOTAFATS up to SKRILLEX.
Honestly, the fill is pretty smooth as well. I'm a little tired of seeing AJA in the grid, no matter how classic the record may have been. It did rank 145 on Rolling Stones' 500 greatest albums of all time, and we all know how much weight the authors of this blog place on the rankings in that list.
Oh, yeah, and OREIDA, that collection of crossword friendly vowels. I also don't like non-winning (or winning) tic-tac-toe rows (OXO). Um, and FORA, a partial.
I was amused by 40A: Asset for a press secretary (TACT), which has been absent in recent examples. MAE West's quotations are always good for a chuckle, and support her ongoing inclusion in crossword puzzles.
Otherwise, I like a good WINELIST, but the other long answers are fairly neutral.
Okay, I liked the theme a lot, and in retrospect I think that colored my view of the rest of the puzzle. But that's okay. Sometimes it works like that. On balance I'll give it a thumbs up.
1A: Early Peruvian (INCAN). C. It's very standard crossword fare.
Fave: ELAINE (31A: J. Peterman employee on "Seinfeld"). I recall with delight the scene where Mr. Peterman has absconded to Burma ("You may know it as Myanmar...").
Least fave: OXO.