Testing the M1 right now.
Ran a lot of envelopes. Good quality- keeping in mind that it is inkjet.
It has it's niche for addressing, adding other graphics+messages you might want to include on the outside of the mailing.
Runs fast, dries fast, feeds nice and is cost effective.
The manufacturer is hoping to to develop some better color controls and additional color profiles in the near future. Right now, the color control is very limited.