Well enough. You can toggle drop with Eagle Claw, you have a -fly in Crippling Axe Kick, and very impressive sustained damage.
It's only real disadvantages are no ranged attacks built into the set. So Spines and claws does better in that respect. And no very effective secondary debuff. Yes the minor mezes are decent, but honestly those being nerfed to 2 seconds really does a number on the utility of the set.
Regardless, Martial arts is still the only Scrapper set that can toggle drop. Pound for pound a lot of MA's attacks deal more damage in the higher tier attacks then many of it's counterparts in other sets.
As an example, Eagle claw does 190 base damage, while Headsplitter does 186 damage. Soaring Dragon does 121 base damage, while Crane Kick does 141
I could go into more detail since my main scrapper is ma/regen. My first 50, and still use him to this day. I hope you get the general idea though since you asked a general question.
Former King of PWNZ
Franziska Von Karma says you will listen to every word I say.
Ok that's all i wanted to know 
Have a lvl 40 Ma/regen and I'm wondering how good will it be at pvp.