We'll begin with the PvE side of the game. The current end-game raid content is relatively forgiving, so there isn't the same sort of elitist shunning of sub-par DPS classes and specs that went on toward the end of The Burning Crusade. Still, it's already clear which of the various damage dealers you actively want in your raid and which you think twice about bringing along.
There are now four serviceable raiding specs for Mages, and the best of those, from a pure DPS output perspective, is the Frostfire Bolt spec. Arcane Brilliance's guide to this spec specifically and others can be found here and here. There are several variations of this particular build floating around, but all of them involve speccing specifically around maximizing the damage output of Frostfire Bolt, and then spamming it almost exclusively in boss fights. Well-geared Mages with this spec tend to finish fights near the top of DPS meters, usually competitive with Moonkin and Shadow Priests, but well below Warlocks. This is a favorable change from The Burning Crusade, where we'd often find ourselves below Hunters, Rogues, Warriors, Hunter pets, Warlock Imps, Shadowfiends, AFK gold farmers who weren't even in the instance, Mechanical Yetis, Compact Harvest Reapers, and our own Water Elementals. It's good to feel competitive again.
Fire/Arcane builds with Torment the Weak can sometimes out-damage elementalist specs, but only if there happens to be a deep Arcane Mage in the group willing to keep Slow up on the target for the duration of the fight Otherwise, Fire Mages fall well short of the damage output of FFB specs, though they are still capable of generating very solid DPS.
Arcane Mages currently finish fights just above Frost Mages, but this is due to change with the release of patch 3.0.8. The main issue Arcane Mages face right now is managing their mana pools in longer fights, and changes like a shortened cooldown for Evocation--which can be talented down to two minutes after the patch hits--should help to resolve that problem. Arcane DPS is already high (when they have mana), and the new version of Arcane Blast and change to Torment the Weak will only improve that DPS. Damage output aside, in the category of raw, unadulterated fun, Arcane is without peer.
As always, the black sheep of PvE DPS remains the Frost Mage. Still, even Frost Mages are better off now than they were in the previous expansion in comparison to other classes. Though they rank below the other three PvE specs in viability, skilled Frost Mages can hold their own against most hybrid classes, and even some pure DPS classes like Hunters and Rogues. Blizzard appears content to leave Frost as the so-called PvP spec for now, and though that is a sad, sorry state of affairs, no changes are on the horizon.
The relative value of Mages as a class in PvE is higher than it has been since the final days of vanilla WoW. We still bring the single most reliable CC spell in the game to the table (though almost every other class now has their own version of it), and our role as vending/portal machines is still as in-demand as it ever was. We're not yet where a lot of us feel we should be, but we're moving in the right direction. Personally, I won't settle for Mages being anywhere short of the absolute top of the chart, but for now I'm encouraged.
The options for killing other players in this game are now many and varied. From simple duels outside Orgrimmar to epic siege warfare in Wintergrasp to the structured battleground combat of Arathi Basin to the intense, match-up driven deathmatches of the Arena system, we can now battle each other in almost any manner we prefer.
In previous iterations of this game, Mages had two choices in PvP. Choice number one was "spec Frost." Choice number two was "die a swift and horrible death." While Frost is still absolutely the spec of choice for pure PvP butt-kickery, many are learning to fear and respect the power of a skilled Arcane Mage. Or at least they're learning to accuse us of face-rolling for the win, or to launch silly and vindictive "nerf Mages" campaigns on the official forums. Either way, they're learning something. Sort of.
Well-geared and skilled Frost Mages are still the kings of survivability in PvP settings, though that specific skillset isn't as valuable as it once was, given today's burst-damage-centered Arena combat. Thankfully, the control and burst damage capabilities the Frost tree offers are still quite formidable, especially with the stun of Deep Freeze in the mix. Frost Mages can still match up well in most fights, though Death Knights, Druids, and Rogues are still lethal foes.
Arcane Mages excel at burst damage and mobility, and Arcane Barrage is the single greatest PvP tool in their arsenal, enabling them to move and burst with unmatched efficiency. Instant Invisibility, high spell resistances, and Improved Blink provide a heightened sense of slipperiness that Mages have never had before. Slow is still an incredibly powerful control tool. Arcane Mages are better suited to the open warfare found in Wintergrasp or the various battlegrounds than they are to Arena combat, due to the relative ease with which they are killed in close quarters.
Fire Mages are still low man on the totem pole when it comes to PvP, due to their need to stand still and cast and their low survivability. Like those with Fire builds, Frostfire Mages can pump out impressive DPS if left alone, but take too long to cast to be truly viable in the hectic realm of PvP.
All of this is well and good, but the most important question for me personally is this: how do we stack up against Warlocks?
The answer--and I firmly believe my nightly prayers for the past two years are primarily responsible for this--is pretty well. Arcane Mages especially can generally pump down a Warlock in time to avoid the nasty, curse-ridden deaths we used to endure so often. Mirror Image is a powerful tool against Locks as well, and should be used early in the fight, to spread the Warlock's initial DoTs around to multiple targets and confuse the pet. It's incredibly nice to finally feel superior to the class I've hated for so long and in so many creatively and disturbingly violent ways. You'd almost expect, now that I no longer get killed by Warlocks on a regular basis, that some of my dislike would fade. You'd be wrong. If anything, my vitriol--and the almost religious fervor with which I express it--has increased. I hate Warlocks with a vigor that extends far beyond the boundaries of mere competitive vengefulness. Although...my hate for Death Knights is starting to move into a similar category.
Is there room in my heart to hate two classes so completely? I say yes.
Every week Arcane Brilliance teleports you inside the wonderful world of Mages and then hurls a Fireball in your face. Check out our recent guide to gearing your Mage for Naxxramas, or our look at the goodies Arcane Mages are getting in patch 3.0.8. Until next week, keep the Mage-train a-rollin'.