I think Reaper has a great future, provided Justin and Schwa don't get bored and decide to do something else. It continually improves in response to users' input. You mentioned Linux, if they pull that off it will be impressive indeed. I'm talking about full equality here with Windows and OS. That's it's a tall order, even for those guys, who are as good as it gets. I would love to ditch Windows and work exclusively in Linux. I only use windows for music at this point, everything else is Linux. But I need to be able to use my sound libraries. There are no Linux equivalents to Cinematic Strings, EWSO, etc.
I started using Reaper about a year and a half ago, because 8.5 Producer wasn't working right. Actually it never did, I must have got a bad install DVD. But when the news about Cakewalk hit, I wanted to make sure I had a good working version of Sonar, so I installed 8.5 Studio, which works fine, and I still have all the features I need. And now that I'm working again in Sonar, I realize it is more intuitive for me. I'll probably go back and forth, eventually settling on Reaper, as Sonar's useful life span is limited at this point. somewhere along the way, Reaper will evolve into just what I need. If not, I'll see if I can adapt it better so my workflow is smoother.