They are fantastic. Korg produces a soundbar for their PA3x/PA4x that costs 3 times as much and doesn't sound anywhere near as good; In fact I've had most of my Korg customers ask to order the GNSMS01 for their PA3/4's, and I had to inform them that unfortunately, the connection is proprietary, so they won't be able to use it.
Incidentally I'm not dissing Korg in general (just their soundbar); the PA1000 has *the* best speakers I've heard on a portable. But I still bought a Yamaha because of the flexibility (samples, audio styles, style library, registrations). But their chord tracking, multipads, *are* better. But a *lot* of my Korg customers ask me "can I get Chinese/Italian/Celtic/Steinway/Bosendorfer sample packs like for the Yamahas?" and the answer is "no, at least not easily".
Mark