THD Bi-Valve or Flexi 50

This may have been covered before but I haven't seen it. I keep a speaker cabinet at home and one in our practice room, and just pack a head back and forth.  Does anyone have any experience with the THD Bi-valve or Flexi 50? They are small and can use a variety of power tubes. I believe they also have an effects loop. Look like they would be easy for an older blues rocker to pack around!  Can they get in the Dumble ballpark with 6L6's installed?  Thanks for your help.