Here's my opinion from a very educated perspective.
My Rogue
http://www.wowarmory.com/character-s...targ&cn=Furbee
My Druid
http://www.wowarmory.com/character-s...ntarg&cn=Ranko
Both have 6051 Gear Score. My rogue may be wearing his t6 for fun.
Druid:
I'm almost arpen capped. When I do get arpen cap I could very easily be a top 5 dps almost every time. In my last saurfang attempt I was doing around 13k dps. That's pretty hot. I don't get hysteria or ToT'd for a dps buff. Saurfang is a stand still, easy fight to make sure rotations for bleeds don't get jacked.
--Cons: Druids lose ALOT of dps moving. Rake doesn't bleed for long and many ferals don't have hit/expertise cap until extreme gear lvls (ilvl 277). Druids have NO talents to increase energy gains. We get what we get when we get it. We do have "seal fate" for crits and combo points, but even our combo point generating skills aren't up to that of a rogue.
Cata changes for Druid:
I'm glad they don't have a hybrid tax anymore. What's the point of having a hybrid tax when the only thing I come out of cat form to do is a battle res? I don't pop out to heal in PvE. I don't pop out to Cyclone instantly (though I could and is fun in some cases). Feral druids, with the help of the new talents, should try to keep up with rogue on dps. Scoping out the new talents makes Feral amazing.
Rogue:
I've played rogue since vanilla. As mutilate (or combat), moving around isnt' always a terrible thing. You keep up SnD pretty easily. Much easier than Savage Roar. There are multiple talents to gain energy faster/gain combo points. Mutilate specs have both. My rogue is about 13k dps as well.
--Cons: Rogues aren't as mobible as druids (30% faster speed for cats and Feral Leap). Apart from that, rogues dont have alot of cons PvE compared to druids. "BUT OH NOEZ, I don't have versatility to HEAL or Battle Res!" Rogues still do top dmg in 264 and 277ilvl gears (except for extremely up there 6400+ gs) then warriors and druids tend to be there.
Cata for rogue:
There are going to be few changes to rogue that is going to be ground breaking. Yay the new smoke bomb....more utility. Yay a heal! They are filling the niche they have been missing for years. DPS-wise very little will change.
Conclusion:
Feral, in my opinion, is a much more difficult class to play and do well. That is even true after the Mangle changes. The "Hybrid Tax" is something that isn't all that implemented thanks to Blizzard's insane ilvl on gear. Everyone wants to be just as good as the other guy. If you have the skill then you should be maxing out your class and it'll be close. For those of you who are rogues and QQ about not being top dps...get better. From my perspective my druid and rogue can both top the meters. It's a little RNG, encounter status, and skill.
I prefer druids currently. They are more fun to play than the 3 button rogue.