pros and cons of the px5d and kaossilator

[pdidit]

I'm looking for a way to add fx to my kaossilator and /or my es1. The norm would be a mini kp .I started looking at pedals and found the px5d. It seems the px5d has many more fx and can do several at once, plus it comes with software and can record. However, it's known as a guitar fx and I don't see where it's ever used with a synth. Is there any reason not to use it with a synth? Is there a better solution? Is it simpler to use than the px4d? Thanks for any input