Not sure where I'd put this in a chart, but I just noticed that the H4 and FB have the main playback buttons to the right of the fader bank while the RH and Nano have the main playback buttons to the left. If you use the main playback buttons (many people don't) it will be a bit of an adjustment to go back and forth between models, muscle memory being what it is. This is a bit of a drag over the H3 line where at least the layout from model to model was identical.
Not sure where I'd put this in a chart, but I just noticed that the H4 and FB have the main playback buttons to the right of the fader bank while the RH and Nano have the main playback buttons to the left. If you use the main playback buttons (many people don't) it will be a bit of an adjustment to go back and forth between models, muscle memory being what it is. This is a bit of a drag over the H3 line where at least the layout from model to model was identical.