I have raided at high levels with both classes, and this is my opinion of the classes.
Both classes offer awesome DPS. However generally in our raids its the 3 Hunters that top the damage meters. Then a mix of Mages, Locks, Shamans (Ele and Enhance) mix it up in the top 8 DPS positions.
This is a general overview of the dps meters as each boss encounter has differing impacts on certain classes.
For example On General Vezax, The casters esp Locks (Damn them and Life Tap) have a fantastic boost due to the residue boosting magical damage. So the Hunters get to suck it up on this fight. The Yogg fight till phase 2 is an even race, but in P3 the Locks shine again.
How your class will fair on the dps charts is situational as well as task dependant and in some cases talent build specific changes make all the difference too.
But overall, on Boss fights and Trash Hunters (in my guild) top the charts consistently followed by the locks and mages with incredibly tight scores. Damn AOE ^^ Hunters used to love this till Volley got hit hard with the nerf bat.
I find however the Lock with a destro build does not require as close attention to CD`s and spell timers. Whereas My Hunter, SV build I find myself micro managing CD`s and spell priority timing. I tend to spend more time watching my timers then the actual fight.
So IMO, the Hunter demands more attention and is less forgiving at high raiding levels. It takes allot more effort to stay top of the meters with the Hunter then with The Warlock.
From a general play style perspective, both are ranged, both have pets (Albeit the hunter has a wider customizable pool to choose from). Both offer raid utility, Hunters offer damage bonus buffs to the raid and the sometimes important misdirects.
The warlock however pops out on top with summoning stone, Soul Stone and Health Stones in the raid.
Both classes offer some form of CC, a warlock can be particularly usefull with Banish and if he has mastered seduce (Focus Macro FTW). Hunter traps imo are weaker in cc if you have an undisciplined raid that keeps on attacking cc targets. The CD on traps can be a real pain, and Wyveren sting has the same problem. Altho on some fights (illidan and Gluth) frost traps saved the day often enough.
I love playing my Hunter and I love my Lock they my two favorites. I do however have more "FUN" with my lock, I find the play style more forgiving ATM and he is a Gnome, whats not to love?
My Hunter I find I need to be more focussed and tend to become "More serious"
The thing that has irritated me allot with these classes however is that the Warlock has always scaled so much better with gear and buffs then the Hunter. Meaning with low level gear the Warlock needs to work harder and the Hunter can almost faceroll and achieve the same dps and better. But as the gear improves the roles change.
GC "Ghost Crawler" is another pain to my hunter atm, it has felt in this expansion that I have had to relearn my hunter more then any other class this year. Because of all the tinkering from Blizz in this class.
On the PVP side in BGs, both classes are ALOT of fun. However in Arena, I have just given up trying to do it with my Hunter. I now only do Arena with my Warlock.
So, if you going to be an arena junkie, I would based on current game mechanics choose a Warlock. However if you going to do heroics, raiding and some BG`s choose the class that you most identify with. I.E do you like the idea of being a hunter traveling free with his trusted companion, shooting from afar and disappearing into the mist. Or are you more of the dark caster, meddling with the unseen realms of power, craving and devouring more and more as you go, striking fear into your enemies?
Anyway, thats my view on it all ;p
