I've got a Harmony 415, the "poor man's Vox", as recommended by Ken Fischer of "Trainwreck" fame when asked about "sleeper" amps, said it's much better than a Marshall 18-watt costing thousands of dollars more. Harmony amps are apparently an excellent inexpensive alternative, and not "Valco" made (not that they aren't great amps too).
Thank you! I think that would be tough for me to answer without knowing which model you are referring to, but I have some a Valco and a couple Supros that will be in this video series in the coming weeks, so maybe you can judge for yourself!