2 battle ship > 20 Burst Fire?

So I know rapid fire lv 1 is weaker than maxed burstfire without SE, but how much of a difference is it? Is the difference actually noticeable when lets say... killing a newtie? or is it more of a DPM thing like when your fighting bosses?

Oh it's very plainly noticeable. Rapid Fire only gets an edge with SE because it fires something like 4 more bullets a second than Burst Fire. Not only that, but Rapid Fire can't be used in midair. Even if you get a point in it for looks, you shouldn't start using it until you can get it at least over level 5.