Hello Jazzbite,
From the H-5 to the H-5P, there were several innovations as well as upgrades. One primary difference is the change to the keybed. The "P" model has a cast aluminum keybed that is more stable and should have added longevity. It's not uncommon for keybeds in good pianos to droop after years of use, and certainly the aluminum will not be in danger of warping. Another innovation is the string termination points in the top two treble sections. In the "P" models, instead of a typical termination in the cast iron, they add larger guage wire for the termination, hardened steel for the upper treble and brass & steel for the lower treble. The idea is to give a more precise string termination for better tone. The cold pressed hammers are another change that tends to be a more stable hammer, meaning less maintenance for voicing. That's not everything, but they are the first items that come to mind.
On the more general note, the production and attention to details in constantly improving. The newer model is more refined in fit and finish than the earlier production.
A used H-5 is probably a very nice piano and it could be a deal. Make sure that the warranty is transferable. It's easy to check with Hailun USA. If the piano was not originally sold by an authorized Hailun dealer, then it would not have warranty. I hope this is not the case, but more than once, we have seen instruments that ... escaped ... from the previous US distributor and were not sold by authorized dealers. The number of instruments is small, but the sellers of these are often very conspicuous online.
I think the Kawai dealer was correct in that Kawai's marketing department never gets any time off.
I tease because they have used so many model names for uprights over the years that they are actually starting to repeat old model names on new, different models.
