I use them as bass amps (200hz on down) in a 4-piece system, but have also run them full range. Mine were revised just before I got them about 3 years ago, but I have heard a friend's original 101s in my system. I don't know the cost, but the revised version has more detail, depth and dynamics than the original--a more refined presentation. Sonically a very worthwhile improvement. The overall character of the sound is the same--it's a very rich amplifier and smooth. It won't wow you with detail, but that's because it's not bright or tilted towards the high frequencies in its balance. It may not be the best amp for rock in that respect, because there is less high frequency energy than some other solid state designs on transients; I personally think the Meitners are more natural sounding. Sounds quite tube-like in its presentation and tonal balance, but it has VERY powerful, and full, bass. I got it originally as a spare in case my Jadis JA80s went down, and now use it, together with the 80's on the midrange and tweeters in the biamped system, because it's a good match tonally with those amps. And they don't weigh 200 pounds, are compact and look great in their mahogany/rosewood cases.