There are many many cool things about Reaper.
I left Cubase SX3 and tried it for a month. My overall impression: For my needs, it's not quite ready for prime time. The dogged resistance to utilizing the concept of tools anywhere in the interface leads to an idiosyncratic, heavy-on-the-hotkeys mode of working, but one can adapt to that. MIDI implementation, however, has a long way to go. People who aren't reliant on MIDI will enjoy it more, but I found it incredibly frustrating to work with. The way it creates and stores files, I also found -- again for me -- to be a mess. Additionally, there's a long list of workaround procedures for working with VSTi with multiple outs. Etc., etc., etc.
On the other hand it does a great number of things really well. Quality, highly customizable signal path. Fantastic routing. Quite a nice list of very positive features, actually.
It's just that the pluses didn't outweigh the negatives for me, though I'm happy I contributed some money to the ongoing Reaper development fund, and I may very well be going back in a couple off years when it's come into its potential.
I have to say that, much against expectations, I found myself breathing a huge sigh of relief when I went back to SX3 and was again putting mixes together in a stable, predictable, fully realized environment.
Cheers all.