Competitively, Sableye is the better one. Why? I'm glad you asked... :P
Sableye: THE BEST abuser of Prankster in UU. With Seismic toss/night shade, you can deal with consistent damage, so you won't be taunt bait. Taunt just matches perfectly with Prankster, and usually shuts down a Pokemon from setting up or putting up hazards. Will-o-wisp is VERY useful when a staller, that way you can take more physical hits with ease, as he doesn't have the best defenses in the world. He even has Recover, which is the icing on the cake. he can also run a risky, but effective set with Swagger + Foul Play.
Overall, this Troll-eye will get you places
Look Here for some Sableye movesets
Spiritomb: Has nice defenses, at 108 BST, but the HP at 50 BST makes it noticeable. Spiritomb has a nice Movepool, consisting of: Calm mind, Sucker punch, Rest + Sleep Talk, but it's kind of hard to set up with this dude. you can try a Choice item + trick set to make this a bit easier, but not recomended. Also, he resides in RU, a place full of All-Out attackers. However, it is very scary to face a RestTalk set with CM and Dark Pulse.
Look Here for Spiritomb Movesets
also, look here on the DB for more Sableye & Spiritomb movesets
