I play a Hofner violin bass knockoff with a naturally hollow, honky sound. This thing sounds very, very clean and transparent, without imparting any color of its own. The notch filter has a huge effect on the tone, more than the eq. Counterclockwise cuts a chunk out of the bass end, giving it a real throaty sound, much like a wah at about halfway down. As you rotate clockwise, the notch moves up to where it's cutting highs, making sound all warm and dark. The shape knob, according to the manual, is more than a notch in that it also boosts certain frequencies related to those it's cutting. In any case, there seems to be a sweet spot whereby it sounds great at one setting, and good but different within about a quarter turn in either direction. The extreme ends were too... extreme. It's an honest 90 watts, and louder than a couple other 90 watt amps I tried. You can make it distort, but only beyond 8 or so with my bass. It's not the good kind of distortion. However, if you don't push it too hard, it has great clean tone and a good variety of it. Not what you'd call warm, but you don't get warm for $280 in a package you can carry in one trip. IMHO, it sounds better than other combos in its price range, and as good as more expensive gear. I'm giving it an 8 for overall sound, and a 10 for the tone-to-dollar ratio. It sounds really smooth when played fingerstyle, and really snappy with a pick. I hate to keep going on about the shape feature, but it's handy to dial in a good tone quickly when switching from fingers to a pick or vice versa.
Can't comment; I haven't had it long enough. It has a generous warranty, 3 years I believe.
I've played guitar for 20+ years and bass (seriously) only recently. I tried several other amps before I arrived at this one. A close second was the Fender Rumble 100 2x10. It had wheels and scary red lights that pulse when you play. I arrived at the Hartke largely because of the shape feature and the 15" speaker. I struggled with the whole power issue, and arrived at the conclusion that the "line out" feature is essential for these little combos. Even the ones with 200 watts don't seem to really cut it. It makes sense that one little speaker just can't move enough air to fill a room with a rock drummer and no PA support. It would be unrealistic to expect that of a combo. So I surrendered some control to the sound guy for a box that I can see over when I put it in my passenger seat... It'll cover most of a stage in your average bar. Your drummer may require a monitor.