Buyers Guide: 5 or 6 Tube Heads That Are 5 or 6 Watts For Under $500 (2019 Edition)

The market has been flush with 5-6 watt tube amps in recent years.  This seems to hit the sweet spot as far as playing at home, small rehearsals, or even gigging (if you're mic'ing the amp).  I own more than several at the moment, and have previously owned a few more.  So hopefully, this quick...