I don't know about all the differences, but I gotta say that I've always read that the TS-9 is supposed to give a punchy "tube" tone. I believe it's suppose to emulate a tube overdrive sound, which it does in an effects box sort of way. I used to own a solid state combo and I bought a TS-9 because of the hype and some of my favorite players used them. I always liked the sound. I still do. But recently I bought a tube combo. Since then, live, I usually don't use any distortion or overdrive boxes. I love the amps overdrive. I haven't gotten rid of the boxes, though. In my studio, I listen to the differences and if you want a good overdriven chord progression, you might wanna go with the amp. If your gonna record a good, distinct lead, the TS-9 will make it stand out. I mostly pro-amps when it comes to overdrive.