I realize that not many have had a chance to try out the Mag600, but I'm assuming it sounds like a Mag300, just bigger. I also know that the Mesa has a tube preamp section and costs three times as much as the Ashdown. But lately I have decided that the warm tube goodness I had to have all these years can only be heard when playing at home or in the studio. To be honest, my hearing is so shot that in a live situation I don't think I could tell the difference between tube and solid state. So imagine you are standing in the music store and you can buy the Mesa 750 or the Ashdown AND another new bass. What to do??