Hiya,
I can't speak to the question at heart as I don't use the poly stuff. Have
you considered other finishes that are a bit easier to repair? Kitchen
countertops will no doubt see a good number of "accidents" and you may want
to consider the possibility of having to re-finish/touch up areas down the
road. My understanding is Poly is a very tough finish but repairing it is
even tougher.
Cheers,
cc