My guess is that someone that has used vim for more than 20 years will never feel truly comfortable with emacs. I say this having started with emacs for a few years, and since switched to vim, now for almost 20 years.
It may be fine for a very casual vim user who wants to switch to emacs but it's too confusing for a vim power user. There are subtle differences that disrupt the flow of my muscle memory. One such example is the }{ forward and reverse paragraph motion. In vim, this is perfectly predictable and delineated by empty lines. In evil-mode, however, it's hooked into the major mode, so it's always changing behaviour as you switch between different file types.