Yes I know
the UC300 has many more inputs and even the AXBB-E has expansion for more via the expansion port 3. I was just comparing the two with screw terminal connections, which make easy setup for the less experienced, no ribbon cables, BOBs etc. , something that attracted me to both the Masso and the AXBB-E, so I bought both to try. But am finding now the Masso while a good unit, is very limited in features compared to the UCCNC software and being a closed system, doesn't allow for the screensets, wizards, macros, plugins etc. than UCCNC has.
Anyway it was just a suggestion that appealed to me and still does, but I will look for a nice micro PC and stick that in the control box with the AXBB-E and have some more fun