Thanks Steve. Sorry I haven't been around much lately. Pesky job.
Recently a good friend (and an excellent bassist) and I did a mini shoot out comparing the Wizzy M, the original Wizzy, a VL 208, and his custom 1x15 cab (all driven with our Walter Woods Electracoustic amps). My friend really liked the Wizzy M, and it certainly did sound very good.
Tom Bowlus has written the best description I've read comparing the two Wizzys, however you really have to hear them for yourself to appreciate what that really means I think.
To me, the two Wizzys do sound similar, yet surprisingly different. I admit I'm very fond of the original Wizzy, including its unique "tone." The Wizzy M is more transparent with less midrange coloration and does seem to have a more extended low end as other have commented. Take your pick; they are both excellent speakers.