All 3 are gimped, but Feral is really fun. It just takes a bit to get used to. Rogues, hunters, paladins, and priests can easily take you down though.
But ya can't knock it till ya try it.
Also for shamans, they are kinda difficult to play. If you go against classes that have fairly high nature resist as Ele, then most of your stuff will be resisted. Enhance does alot of damage, but it's survivability is low, such as a feral druids. And Resto is just too difficult to play. I've seen very few people that can make it work, but it's not good for when there's alot of burst occuring. And this so happens to be a super bursty bracket.