Are all energy weapon effects a chance thing or do some do it constantly. Like does each disruptor blast debuff or just have a chance to debuff? Each plasma hit cause a plasma effect?

It's all chance based, but a lot of fun when it happens I've seen phaser array knock down all shields on an enemy for 2-3 seconds. Fun!

There is a lot if info on energy weapons here if interested:

http://forums.startrekonline.com/showthread.php?t=88576

Is the chance different for the dif weapons? Cause if it's all chance based with equal chance for each then it seems phaser > polaron in that case, especially when you consider what the skill point cost is of maxing polaron weapons.