I've purchased many engines from both suppliers.
Haven't found much difference between the two except that the PKS engines are packed better, so there's less of a chance of damage.
But then again, I've never gotten a "perfect" engine kit. There's always something wrong, whether is be scratches, dents, bent studs, bent fins, etc. As long as you know what you're getting into when you buy one, you'll be okay.
Personally, I would get a Grubee kit. They are still rough around the edges (all of the HT kits are), but are the best for just a little more money than the others.