First of all I would generalise and say whatever Mach3 could do, if one day UCcnc could do it, this application will be the much improved Mach3 replacement.
I am hearing mainly very good things about UCcnc - excellent stability, it doesn't break tools or chew up jobs, vastly improved CV trajectory control, plenty IO. I've certainly got my eye on UCcnc but it's just missing some goodies at present that I guess I take for granted coming from Mach3.
I'm into plasma and am working on my own home brew system and torch height control. UCcnc doesn't have corner lock at present (Mach3 Anti-Dive), something needed for plasma cutting. I'm going to use Modbus to communicate parameters (nothing where timing or speed is needed), so I was sad to see no PLC/Brains type functionality in UCcnc or Modbus type communication for external devices. My aim is to have all control settings for external devices on screen and passed to external devices. Likewise parameters from external devices will be passed to the cnc controller screen and be displayed there. I know this could be done is a plugin for UCcnc but I have no idea where to start there (any instructional info on how to start writing plugins for UCcnc).
A graphical screen designer like Mach3 has.
Good teaching materials. The biggest hurdle I have always found is finding info on how to implement all available features in software. Time and time again I find out the software can do this and can do that, but that revelation came to light in what I consider all the "difficult" ways. You found out from forum posts or whatever, from asking a hundred questions, from Googling for the info, etc. If you have good quality videos and written manuals that clearly spell out what can be done and how it can be done, that saves users vasts amounts of time in the learning curve. Word of mouth will then lead to a lot more sales. The one thing I hear repeatedly in the Mach vs Linux debates is how easy or difficult it was to get up to speed with learning the program and how to customise it. Lcnc appears to be a lot more stable than Mach3 but the ease of learning seems to have pulled a great deal of people to Mach3. But I even found Mach very limited in GOOD teaching materials. TP above has been huge in my learning of Mach3 (thanks again Terry). Terry has taught me stuff about Mach3 and I've thought that's extremely useful but where the hell did he find that out. I think designers can get so engrossed in making the software and they are so high up with their knowledge that maybe it's hard for them to come down to the level of someone looking at their software the first time, especially if they are new to the cnc game.
Keith