Personally, I think Dragon Dance Feraligatr is better.
The reason for this is that Feraligatr's base Speed (78) is high enough to make it worth while to speed it up, but not low enough that it'll make no difference (as in the case of Avalugg, or Ferrothorn).
Further, Feraligatr is not bulky enough to withstand multiple (super effective) special attacks when it's slower than its opponents which will try to revenge kill it.
Besides, both Grass and Electric moves are more likely to be Special based, so raising your defense makes no difference. It's better therefore to raise your speed and try to sweep than risk being revenge KOed.
I do want to stress this: Sheer Force Feraligatr is much, much better than Torrent Feraligatr, so if you're serious about transferring it all the way from Crystal, then that's something you should keep in mind. The best set imo is a Sheer Force Feeligatr with Life Orb, having the moves Dragon Dance, Waterfall, and any two of Aqua Jet, Ice Punch, and Crunch.
