In a close counters melee battle, balls are really your only alternative. The beam makes you a sitting duck, but in a situation with a lot of disance the beam is good. I heard that the balls lose power as they fly, so i guess the beam is more powerful.
"I still think that beam jumping is a bit too overpowered. I mean, if they could move that fast beam jumping, why bother flying from one side of the planet to the other when a single generic beam can propel them that fast."
Control, you can't control yourself well with a beam, while the swoop allows you to have great manueverability.