It would be interesting to know if the One even works with myharmony. I had the impression that only the newer One Plus worked with myharmony. So if you don't mind, give it a try and let us know.
In any case, as Bryan said, myharmony is quite limited on the OnePlus - no sequences, no additional commands in activities, no activity reordering, no device renaming, no pronto hex import, no IR signal adjustments (repeats), and probably a few other things I'm forgetting. Myharmony certainly looks prettier and has a nice drag and drop interface for assigning custom buttons, but that's about it. I hope the new owners totally rework the software, but I'm not holding my breath.