Monks as a whole are alot of fun, however all the specs have serious disadvantages in the 24 bracket.
Windwalking(Dmg) - Kickass moblity, and pretty legitimate damage if you have PvP Power enchants and solid agility, but without some sort of pocket healer watching them they really cannot be seen as a serious class. That being said, the week or so i spent trying them out was alot of fun, i took people from 100% to Zero a few times with FoF (fists of fury), and flying serpant kick is 400% move speed for 60 yards on a 25 second CD, making it possibly the best mobility ability in the bracket besides maybe drood's travel form.
Mistweaving(Heals) - Also fairly decent mobility, and a good combination of heals and damage, being that serpant stance turns 200% spellpower into attack power, you still hit very hard. But the only heal you have to use, is channeled, and serves as a giant arrow pointing to the healer, in addition it really doesnt heal for that much, it can easily be DPS'd through, and monks only have one dmg reduction cooldown minuas any racials they might have.
Brewmaster(Tank) - Probably the most "viable" of the three in that they are given a perma aoe ranged stun, and can easily reach very large amounts of HP at 24. In addition, simply having roll makes then pretty mobile, but not quite on par with windwalking. They are again hindered by the fact that they do not have any kind of self heal, but the perma slow makes them very solid kiters, second only too droods.
The toon that i played was as best i could get him geared in 3 days, had rings, some BiS gear, no AGM's, +16PvP Power, and BiS enchants on BOA gear, so i had a pretty good idea of what they were capable of. Ultimately windwalking is the most fun of the three for me, by far. It is the equivelent of what i wish Enhancement shaman was. Really good mobility with strong burst. Monks are a good class to dick around with, but if you want to be considered for a War Games or the like, i would stick with what you have.