My own experience of speed feeds is a bad one, I don't play much tourney where they're apparently useful but even then they have their setbacks. Firstly poorer speed feeds will lose you a few balls (5-10 or so) each time you reload as they'll just roll off and not go in. Watch a still of a breakout and see the paint fly, moving the gun quickly in a direction gravity doesn't favour will cause some paint to fall out, especially if the speed feeds a little old and saggy. If it is old and saggy it can also lower your hoppers capacity by 20 odd balls just by the tips being in the way.
On the bright side it makes your reloading a little quicker, each to their own, the best way to decide is have your own experiences with them. Mine were obviously bad, but make your own decision.