If my daughters had asked that question they would also have said, 'Dad, give me the short answer'.
Short answer, yes, this is the version for sale, I have cut a 27mm 1.5mm internal thread for my spindle on a timing gear that worked the first time with the pmdx411 controller, yes there are a few other bugs.
The long answer. Very few hobbyists are using Mach4(m4) in the lathe mode therefore very little attention is being paid to it. NFS can't afford to provide the support to a hobbyist who paid $200 and they have been upfront about the amount of suppport to expect. There are a couple of NFS people who monitor the forum and chime in when users get stuck and no one can help answer the problem. I'm sure the industrial version has had more scrutiny.
Because m4 motion control is now solely the responsibility of the hardware vendor it is unknown which and how the functions have been implemented and tested. When I switched to m4 earlier this year I had a uc100 controller and they advertised that they had a m4 plugin. It turned out they had not tested it on a lathe and it did not work. I don't know if they have subsequently upgraded their plugin. The pmdx411 was a direct substitute that meant I didn't have to change any hardware or wiring so I tried that and have been pleased with its performance. I don't know if any other vendor has implemented threading and tested it on a lathe.
The lathe version version will do most things that the hobbyist wants if they are using it in a traditional manor (run GCode files). It is designed totally different from Mach3, implementing Fanuc gcode, lua as its scripting language and has a built in screen editor (that has a few annoying but not fatal bugs). Learning the scripting paradigm and language has a steep learning curve.
Having said that I will not revert to m3. I'm closing in on retiring and enjoy the challenge.
HTH
RT