Haven't used it on ham, although I do have some VHF capable NXDN radios.
I am using it on my trunked system at work. It works really well and if set up correctly, the audio is really good. I suspect, however, that not all hams would set it up right, "out of the box" settings usually are not right for all applications.
It is limited by available radios. I think I've looked a few times for NXDN repeaters near me, and the only ones were UHF.