Looking to upgrade my Boss GT-Pro... looking for a unit that has good presets to mimic the sounds of Vai, Satriani and Petrucci. I contacted different music dealers and (of course) they all recommend what they sell. My options: Eleven Rack HD 500X (or preferably the pro rack mount) Digitech GSP1101 I heard good youtube demos of all, and a few of the Digitech's blew me away. However, I never heard specific patches of the three above individuals aside from the Digitech and so can't comment. Any recommendations?