Mhm, I was checking their stats and they don't look so great - Serperior has a reaaaally nice speed but lacks so much power.. with so much speed one would think it would at least be a good status inducer pokémon, but I believe it lacks the bulk and movepool, judging by its stats. Anyway I'll go with it just because I prefer it over a pig and a... whatever the water-dude is xD
By the way, to keep the conversation X/Y related, I had the closest battle of my little poke-life today. Both me and my foe had only one pokémon left, he had a 1HP Blaziken due to Focus Sash and my Mega Gyarados was at 38 HP. Obviously, he was at +123123 speed due to that retarded ability, but he decided to go for High Jump Kick instead of whatever fire move he had (it was a baton passer Blaziken, no mega, protect/baton pass/hi-jumpkick/fire move I assume since it gets STAB but I didn't get to see it anyway). Well you know how it ends, he missed the kick and killed himself. I would have gone for the fire move even if it wasn't effective.. I mean I only had 38 HP left...