I began with Pro Tools 12 years ago, been using Reaper exlusively for the last four-five months.
To me, it took a long time before I gave it a serious try, because I did'nt find it visually inspiring, but the functionality and the results I get using it is as great.
Found out that the creator is the same guy who made WinAmp many years ago, and that's big Plus to me.
Highly recommend giving it a chance!
One of the many nice features of Reaper is themes. If you're coming from ProTools, there is a ProTools theme that makes it look like PT. Same for Logic themes. And there are others that are not based on other DAWs, but that you may find more to your liking visually.