I'm amazed at how quickly I can blast through mobs of my level, and even a level or two above. With Frost Nova, if I time it right, they never touch me. If they do get too close and it's a sticky situation, Blink saves the day. Polymorph is also a fantastic tool to use against groups. I feel like an uncontrollable damage machine when I play, most of the time.
Sadly, all this power comes at a cost -- a mana cost. I'm constantly getting low mana at the wrong time; mana management is the next thing I have to learn. If I'm OOM, or with Blink and Frost Nova on cooldown, sometimes I just can't run fast enough to get away; I've suffered fewer deaths than I'd expected, though. Grouping with a priest makes for a winning combination, with additional ranged attack power and those oh-so-convenient heals.
As it's an alt, my main trouble with the character is remembering to use the right abilities at the right time. For some reason I've developed a habit of firing Frost Nova instead of Frostbolt to pull; funny the first time, frustrating the hundredth. I forget about Polymorph at the worst moment, and when I'm OOM, Evocation doesn't enter my mind. I'm the ditziest mage this side of Thousand Needles, but I'm enjoying it -- more so than the rogue, as the mage is truly something different from my druid.