I absolutely love Pianoteq 4.5 - For me there's that point where a product is so good already that the updates tend to be really incremental, and I think that's where Moddart (two ds? Two ts? Always forget!) are. I'll probably upgrade at some point, but I'll probably hold off until they come out with an add-on pack that I can't resist but that requires v5 to run.
I think this is a company that embodies everything that's good about music tech: Revolutionary approach, great product, generous upgrades, and top-notch add-ons. Would *love* to see them tackle some non-typical pianos when they decide what to model next, especially if that meant working on some more uprights.