Ilija,
I give the Peavey KB300 a "Thumbs Up". I've had mine for seven years and it is a very dependable amp. I have used it for a personal monitor in our seven member Beach/soul/variety band,
www.thecollegians.com as well as a one-man-band amp.
When I use it with the band, I transport it in a custom built road case (with wheels)and put it on the equipment truck. When I use it in my soloact I carry it in my Dodge minivan without the road case. I use a small two wheel hand-truck ($20.00 US)to move it around. I have installed recessed handles on each side which makes lifting the amp into and out of the van much easier.
As for the sound quality, it is very, very good with my Solton X1 and Roland G1000. The 15" Black Widow speaker and piezo tweeter get the job done even in fairly large rooms. It pumps a true 150 watts rms. Caution: over the years, not all KB300s came with the Black Widow speakers. I would insist on th BW. I recently acquired a new Roland KC300. It sounds fine in my family room or basement music room but it does not measure up to the KB300 in bass response, projection, and coverage of larger spaces (or those with a lot of carpeting and/or acoustic ceiling tile).
I like the way Peavey implements the three channel set up. In one of the channels you have your choice of XLR or 1/4" input. Vocals sound very clear and distinct through this amp. All in all, I would not consider selling my KB300 for less than $400.00(US). Even though it is 7 years old it is in new condition and sounds better than any $400.00 amp I've heard.