Kamyanets-Podilsky is historically important to the Polish and Ukrainian empires, playing host to defence against several invasions: Ottoman, Mongol, and Tartar among them. The old town is a beautiful castle-island, with an older castle just across a stone bridge.
That being said, I didn;t have a particularly good time here. A couple of pictures that I liked and a decent pizza at one of the few open restaurants I could find in the Old Town were all Kam-Po had going for it. Thats not to say that others shouldnt visit, but I would suggest not doing it during the off-season.