If you're just starting out, or playing as an opening DJ... then you need to learn to play on whatever gear might be present on any given night. If you can only Dj on a controller, then you won't get booked in many legitimate clubs. The last thing a club owner wants is to have $5k worth of gear in his booth and his opening DJ roll in with a $200 controller and start unplugging and repositioning the booth, making it more of a hassle for those to follow. Doesn't make sense and it looks like a crutch. It's mostly image, but it reflects on your ability (or lack thereof). My advice: learn to play on CDJ's, but advance your skills on whatever you choose.