The singular rather than plural title makes it instantly clear that M-Audio's grand piano library contains just the one model. Specifically, this is a Yamaha C7 - a piano that's been sampled many times before.
By today's standards, this is a relatively small piano (the entire disc contains less than 500MB of content) and when you compare it to some of its multi-gigabyte rivals, this shows.
It doesn't sound quite as expansive or rich as other instruments, so if you buy it as an upgrade, you could be rather disappointed. That being the case, this is hard to recommend.