A lot of people play acrobat because it's less difficult to handle. Acrobat can just get up in the opponents face, windmill kick the shit out of them, AoE them, and get the **** out of there.
HOWEVER - Acrobat is substantially less useful for PvE, and is more suited for PvP. I'm not so sure if that's still the case in the level 45 job advancement, when they have the ability to become Wind Walker/Tempest. I don't have enough/any info about that personally, but I'd expect they'd get more useful for things like raids after that job advancement :v
I'll personally be playing Sharpshooter, with the intent to become Artillery when the later job advancement is made available. A magic-based bowman class just seems intriguing :v
But yeah, I used longbow the entire time during CBT and loved it, so I figure it's probably the proper choice for me lol.