Unsurprisingly, given the size of the library, the quality is excellent. The velocity layering, for example, works seamlessly, so making a performance using piano keys or pads feels very natural.
Overall, The Progressive Foundry has a slightly softer sound than many rock kits. It definitely has a touch of 1970s production about it, which is a bit of a trend in drum libraries at the moment. Now that drums aren’t going hot to analogue tape, not having that ultra-hard edge is often a good thing. That said, the kits still have power and the ability to cut though, and there are plenty of drum options to choose from if a particular preset is not quite cutting it. (Kick and snares, for example, range from thick and fuzzy to tight and clean). Using EQ and processing is one way to shape the sounds, but just simply adjusting the mic balances has a massive effect.
In summary, this is a high-quality drum library/virtual instrument with flexibility within the bounds of the rock genre.