I have owned a TH500, loved it, except it is a very vintage voiced amp, and to my ears, I could never get anything except a vintage sound out of it so I let her go. Currently own a Mesa M6, until it gave up the ghost 2 weeks ago, it was one of the first gens and the MOSFETs shorted so I had to send it in for the "upgrade" which is now a repair, waiting for its return, loved this amp, but it too had its very own distinct voice, and again I could never get anything but THAT tone from it and she is going up for sale upon her "upgrade" and return to me. Currently also own a MESA Subway D-800 for my practice/backup rig, love it, nothing bad to say about it at all. I currently own a GK MBF800 which I bought to replace my down M6 as my main live rig amp, and let me tell you, it is awesome. Nothing like anything I've played through before. I have been playing for 35 years and I have finally found that tone I was looking for, besides; this thing is a HAMMER, it feels like it can punch through concrete, after 35 years I finally know what the highly subjective word PUNCH means...at least to me.