Hey I see a ton of topics about 5v5 but I rarely see any 3v3 come up.

I'm currently leveling a lock, mage, priest with ultimate goals of pvp and arena in mind.

Is there anyone out there with any experience with either this setup in pvp or in the 3v3 arenas in general?
I'd really like to step up to the 5v5 but cost constraints are holding me back from buying another machine that would be required to run it at a fairly decent speed.
Thanks in advance for your help and time.

Best wishes