Yeah, for me to upgrade it would probably have to be everything as good as the RM2 plus colour.
I'd be happy with very basic colour that is adequate for highlighting, but not if it was at a lower resolution or was a drop in performance.
I don't see much advantage for a relatively small company to do anything other than software improvements until then.
It's expensive, if it isn't expensive for you, go ahead, if you could use the money on something else, then do that, a book and a pen will be fine.
It's best use is for annotation of books and articles