I just downloaded this morning and have only been playing for a bit, but my first impression is that this feels very authentic and is extremely well done overall. I am seriously impressed - great job!
In the absence of alternatives, I've been using Pianoteq's historical instrument collections whenever I want to play on a fortepiano. They are actually not that bad (more realistic sounding to my ears than their modern pianos), but I've been waiting for some developer to offer a decent sampled fortepiano, and this is the best option I've come across yet.
Speaking for myself, I've been interested in early historical pianos since I was young, and while I would never give up playing on a modern piano, I do find them evocative and attractive on their own terms, as well as useful for understanding what kind of sonorities composers of the time might have had in mind when creating their music.
The Clementi fortepianos are among the very earliest (I believe he basically invented them), but what I've always found interesting is how pianos from this era were continually evolving from decade to decade, and had significant variances from maker to maker, so that an instrument from late 18th century could sound quite different than one from the early decades of the 19th, and so on.
I've always hoped that someday a developer would put together a collection of fortepianos from different eras and makers - kind of like the Pianoteq collections, but sampled instead of modeled. I feel like this a rather large gap in the current VST market, so if you ever have the opportunity to take on a project like this I think it would fill a really important niche, and be a valuable service for those of us who are interested in these types of instruments. Speaking for myself, I would happily pay for such a collection, and I suspect there would be a fair number of others who would as well.
Anyway, great job and keep up the good work!