I've just finished porting over a mid-sized project to Reaper. There are quite a few synths in it, including 10 instances of Reaktor all running at 96kHz (although the project itself is 48kHz). And then there are a lot of instance of CPU heavy plugins like Decapitator and Passive EQ. If I had all of these synths on in Sonar, I'd have to run the project at 1024 samples to hear it without any glitches. Anything lower than 512 samples and it would be completely distorted. 
 
In Reaper I just tried running it at 64 samples, with all synths turned on, and not a single glitch! Not only that, I can loop small sections of these synth tracks and they loop without the explosive pops and clicks that I get from Sonar when looping synth heavy projects. 
 
I mean I was expecting a performance boost but this almost seems magical!

Having followed REAPER since it was still in alpha/beta back in 2005-2006 and a registered user since the v1.0 release, I would have to say it is down to the vision of the main coder Justin Frankel and his unique programming skills. He coded REAPER from the ground up to be a streamlined and efficient DAW app. He does not rely on any OS routines/libraries/code like most other DAW's and just creates his own as needed. That is why it only takes a few seconds to download, install and even update. Because it does not rely on the OS, you can even run REAPER straight from a thumb drive. It is totally self-contained and the small 10MB installer has everything you need to run the app on it's own. While many other DAW apps are focused on keeping their legacy code working as they add new features and whiz bang graphic eye candy, Justin continued to concentrate on keeping the underlying code in REAPER as streamlined and efficient as possible. Justin's mantra has been that eye candy and extraneous features (adding fancy graphics, useless loop libraries, even more plugins and such) is secondary to stability and efficiency in a DAW app. There have been countless DAW app benchmark tests done over the years and REAPER has consistently been at or near the top in all of them. Those of us that have used REAPER over the years have known this for a long time now.
So when others say that the REAPER GUI is ugly or how can a full featured DAW app be so inexpensive (some even think it is free) and be any good or considered "Pro", you can only roll your eyes at their ignorance. 
 
Here is an interesting video interview with Justin Frankel from 2015 that gives some insight into his ethos and how REAPER came to be.
 
https://www.youtube.com/watch?v=vfaQrOeb_F0
 

I have to admit (to my own shame) the first time I tried Reaper I dismissed it out of hand.  And then SONAR did it's thing, and now I'm trying Reaper again.  As stated above this thing is pretty amazing.  It feels like the learning curve is steeeeeeeep, but maybe that's just me.  Still for $60 . . . .  Plus, you can make the darn look just like the REDD desk from back in the day at Abbey Road.  Reaper is definitely a force to be reckoned with.  

I have also read that Justin uses older Borland C++ compilers on parts of the audio engine, to keep from introducing lots of overhead for things that will never be used. The same code compiled with a Dot Net version of C++ would add boatloads of extra junk in case we might need the audio engine to stream audio from the internet or something.
 
I used to subcontract a guy to program custom stuff for the company I used to work for and he did the same thing. His applets that he coded for me were always tiny, completely independent of any runtime libraries, and dragster fast.

I'm loving this DAW, it took a while, but now that I'm up and running it's become the goto app for me. I had demoed it back when it was free, but it was still to raw and I gave up on it quickly. Since Sonar's demise, I tried a few DAWS and kept coming back to Reaper for it's efficiency and light footprint. I love how I can set and configure icons for my most commonly used tasks eliminating menu diving and with all the docking capabilities it's easy to set things up and put multiple docks (up to 4) in 1 dock anywhere on the screen. I'm just waiting on them to integrate ARA 2 some time later this yearn which they have said is coming. So far there's been nothing for my workflow that I can't do. If you like the Tungsten theme for SPLAT, go to reaperstash and download Hydra. It looks a lot like the current Sonar theme. 
 
The CPU use is great as well. SPLAT was good, better than a lot of DAWS, but Reaper is very solid at 64 samples for me and I'm using an older firewire interface. Yes there have been some crashes, but I chalk that up to buggy vsts like Drumagog and a few others. Basically the same things that crash Sonar for me crash Reaper. 
 
 
 

Billy Buck
Having followed REAPER since it was still in alpha/beta back in 2005-2006 and a registered user since the v1.0 release, I would have to say it is down to the vision of the main coder Justin Frankel and his unique programming skills. He coded REAPER from the ground up to be a streamlined and efficient DAW app. He does not rely on any OS routines/libraries/code like most other DAW's and just creates his own as needed. That is why it only takes a few seconds to download, install and even update. Because it does not rely on the OS, you can even run REAPER straight from a thumb drive. It is totally self-contained and the small 10MB installer has everything you need to run the app on it's own. While many other DAW apps are focused on keeping their legacy code working as they add new features and whiz bang graphic eye candy, Justin continued to concentrate on keeping the underlying code in REAPER as streamlined and efficient as possible. Justin's mantra has been that eye candy and extraneous features (adding fancy graphics, useless loop libraries, even more plugins and such) is secondary to stability and efficiency in a DAW app. There have been countless DAW app benchmark tests done over the years and REAPER has consistently been at or near the top in all of them. Those of us that have used REAPER over the years have known this for a long time now.
So when others say that the REAPER GUI is ugly or how can a full featured DAW app be so inexpensive (some even think it is free) and be any good or considered "Pro", you can only roll your eyes at their ignorance. 
 
Here is an interesting video interview with Justin Frankel from 2015 that gives some insight into his ethos and how REAPER came to be.
 
https://www.youtube.com/watch?v=vfaQrOeb_F0
 

Very interesting insight, thanks.

jude77
I have to admit (to my own shame) the first time I tried Reaper I dismissed it out of hand.  And then SONAR did it's thing, and now I'm trying Reaper again.  As stated above this thing is pretty amazing.  It feels like the learning curve is steeeeeeeep, but maybe that's just me.  Still for $60 . . . .  Plus, you can make the darn look just like the REDD desk from back in the day at Abbey Road.  Reaper is definitely a force to be reckoned with.  

I'm actually finding it easier to learn than other DAW's. Kenny Gioia's excellent "Reaper Mania" channel on YouTube helps a lot.

emwhy
I'm just waiting on them to integrate ARA 2 some time later this yearn which they have said is coming.

This is exactly the flaw of Reaper for me (for Melodyne). But on the other hand I like their efficient code, the configuration possibilities and their licensing!

On their forums I got the impression that while ARA2 is pretty much ready to go, there are currently no plug-ins that work with that format......yet.....as soon as that happens schwa said that they will introduce ARA2. Here's the exact quote:
 
There aren't any actual ARA2 plugins released yet. We'll add our support to prerelease builds as soon as there are.
 
And the whole thread:
 
https://forum.cockos.com/showthread.php?t=200297

sharke

jude77
I have to admit (to my own shame) the first time I tried Reaper I dismissed it out of hand.  And then SONAR did it's thing, and now I'm trying Reaper again.  As stated above this thing is pretty amazing.  It feels like the learning curve is steeeeeeeep, but maybe that's just me.  Still for $60 . . . .  Plus, you can make the darn look just like the REDD desk from back in the day at Abbey Road.  Reaper is definitely a force to be reckoned with.  

I'm actually finding it easier to learn than other DAW's. Kenny Gioia's excellent "Reaper Mania" channel on YouTube helps a lot.

I'll check it out.  Many thanks for the heads-up.