^Personal preference really.. some people claim neutron has more grip others say proton. For the most part is like comparing champion/star (but even nicer blends than that junk) both are premium plastics and basically the same regardless of the mold.
I find proton plastic to be faster/maybe a titch more glide but a lot of my proton molds also have more dome than their neutron counterparts. Plus now they are putting sparkles in the proton ooouuu aaaawwww!!