I inherited a pair from my uncle. They sound a little harsh to me. They have lots of bass, especially for their size, and it doesn't sound boomy or bad. But it is a bit exaggerated. Very much rock or party speakers. They're not efficient, and they don't like power. I burned up a pair of woofers pretty bad driving them with my Phase Linear 700, just trying to get a decent listening volume in a large room. Even a pair of AT-8 Cerwin Vegas can go louder, because they're far more efficient. So... kind of a pass. They sound better than the AT-8, have more bass than the AT-8, are good for rock music, like the AT-8... but fail for volume and power handling. Probably okay for a small room, but for a living room they're inadequate. I tried to use them as rear channels paired with Cerwin Vega VS-150 mains, but they were too under-powered to keep up with the Vegas, and I was at risk of blowing them out again. I replaced them with, of all things, Pioneer CS-922A "kabuki" speakers. Those work well for my rear channels and can handle a ton of power at retarded listening levels. And the Pioneers sound less harsh to boot.
I will say the KG2.5s do sound better paired with a tube amp, or a vintage receiver, but they're still not great. Pretty much everything else I own, except for the Minimus-7 and Optimus-77s I have laying round, sound better.
Charles.