I'm a long time Pro Tools and Adobe Audition user. Downloaded Reaper yesterday and mixed for a few hours. I tested on an old G5 PPC and a WinXP PC. I'm very impressed.
It found my hardware with no issue: 002 on the Mac, sound card on the PC.
I find the interface pleasing to look at plus you can customize.
Checked the buffer settings. Easy.
Imported some tracks. Very easy.
Created a drum sub-mix using sends. I like the press-and-drag routing.
Tried out a few plug-ins. Everything works.
Had a little issue with some phasing. But it was an outdated plug-in with no latency compensation. Not Reaper's fault.
Rendered the mix, no problems.
I haven't tried to track with it yet. But mixing with it was great and I'm now addicted. I hope it tracks as well as it mixes. I'll try recording with it today and I may have a few noob questions for you guys who've been using it a while.
It's definitely powerful software and it's really great, I just couldn't get used to the "feel" of it. There's a few features I wish Pro Tools would steal, but overall I like the mix window (especially the way it handles routing and plugins) and overall editing in Pro Tools better. Just personal preference