Def Sony A6000. I just bought one for myself. Second hand tho. It fits your price range. I remember when Sony first introduced A6000 they claimed that it's the fastest AF in the world. And even after 4y down the track, I still think AF on A6000 is pretty impressive. 0.06 seconds for the Sony a6000 to lock on to a subject is faster than many other mirrorless cameras. No doubts about it.