Summoner is definitely in my top favorite classes. It's an extremely simple gish concept that i dont really see in similar systems. In essence, you're a subpar caster that commands a subpar martial, now I made that sound bad but the way they made that work just makes it extremely satisfying to play. Also just being an all traditions caster makes them variable as is, the only summoner I have played is occult but I do feel that's my favorite tradition for summoners. Occult tradition does lend well to the bounded casting and makes for a great buff caster. I can also imagine once the remaster comes out and runic weapon/body starts scaling that primal summoners will be an amazing self buffing class.
also I'm still waiting for that aberration eidolon, paizo. I'll be patient but one day...