For a Newfoundland circumnav record attempt, I chose the GPro as I wanted a faster hull than the Explorer that I had been using.
You are correct that the chines will suffer damage from rocks, but it is mostly cosmetic (gel-coat). A keel strip and chine strips are a good idea in rocky areas and should help prevent damage.
GPro layup is heavy but is pretty tough - I "bottomed out" on rocks more than once, fully loaded and felt the hull flex but absolutely no damage (some flex is a good thing). By the same token, I cracked the hull on a very well-made but lighter layup in a (round hulled) Rockpool the year before in Newfoundland, when a wave trough caused me to bottom out for just a second on a rock (craaaaaack).
The GPro does like to surf (if not too overloaded). During a 93km paddle, crossing Placentia Bay in NFLD, I was occasionally getting runs up to 19 kts (20mph) in steep following seas.
I have owned a Nordkapp (HS), it's a fine kayak as well. It's largely a matter of your personal preference. I do like the "nod" to Greenland "style" in the GP, although it is far from a Greenland kayak.
Speed of both is good, but on flatwater they are significantly slower than something like an Epic 18x.
If you wear boots, make sure that you have sufficent footroom in the Gpro.