Disclaimer! I do not have, nor have seen the latest NV engines. My comments are based on the old Norvels.
If I were buying an engine right now, it would be the NV. First, it is now almost the only game in town, as the AP seems to be discontinued. Second, it comes with a CL venturi, so is cheaper than an AP combined with the cost of a now unavailable aftermarket venturi. It is properly equipped right out of the box.
With the Galbreath head, the Mk 1 Brodak is an alternative worth looking at, they run with near TD power and Medallion fuel draw, a great combination. The caveat is that I have little experience with them on a long term life basis. The NV is probably cheaper and likely more reliably proper fits than this combo too.
I still have a couple of NIB APs, and you may be sure the cranks will be well polished before they ever run. Chuck a cut-off bolt into your drill, mount the crank, and run it at low speed. 2000 grit paper with oil followed by Simichrome on a paper towel will provide a mirror finish. I published this recently in the Cox newsletter with photos.