Got to Silver with Feraligatr, really wasn't that hard he's pretty good in the current metagame. The set I used:
Might look awful at first, with the only redeeming thing being aqua jet which Azumarill does better, and while his coverage isn't great and he's not immediately strong he does a couple of really awesome things. First thing I loved about him is that he breaks through Ferrothorn and Jellicent at +2, which with max HP wasn't hard to get at all. Aqua Jet in the rain is really strong for priority, and it's strong in general after the +2 boost. Torrent makes him really dangerous since often the way I'd set up was on an attack I knew would hurt but wouldn't kill, and then I'd get to torrent very fast and basically smash my way through the other team.
Obviously he needs to be on a rain team, but other then that I didn't give him any additional support other then SR which every sweeper wants. He more than pulled his weight and was really a surprise for me, as I figured he'd pretty much just be a revenge killer and occasionally sweep a really bad team. You have to wear down the other team a little before he can go through and he does have some things he just can't break but overall in the late game he's a definite force. In short, I loved him.