Interesting thread... I already voted but figured that I might as well share my story, because why not
I'm using Live as my main DAW and as such I also use the RRP within Live (what a surprise, eh?). It may sound casual enough but it's only quite recent since I "officially" said goodbye to Reason 10 & ReWire and more or less replaced it with the RRP.
Sorta...
Reason 11 has been a huge love/hate scenario for me and I plain out disliked the RRP with a passion at first, so I stuck with Reason 10 (which still supported ReWire). I really think Reasons sequencer and mixing panel are often underrated, but that's just my opinion. I've been using Reason since version 4 and I've
always used Reason as an expansion for my Live setup. Live has been the heart of my home studio for over 10 years now, and I love it. I've reached a point where I no longer want to miss out on Max for Live and/or Max, that stuff is so darn extensive.... Although I have a regular Max license it's simply very easy (and useful!) to be able and build devices or effects and have them working right within your favorite DAW "just like that".
Alas, this is about Reason and not necessarily Live
At first I disliked the RRP, with a passion. It's because of that why I discovered that you could easily use rack extensions with Reason 10 even though they were developed for Reason 11 (Scenic and such...). Of course the former Props changed and improved things (such as a functional tab key) and that changed a lot for me.
However, I still had to cope with missing out on a second "parallel" sequencer. Seriously you guys: once you start exploring the potential of having 2 sequencers working together you're opening up a Pandora's box, but in a (very!) positive way... depending on the sequencer of course, but you can do
a lot of crazy stuff there. It takes getting used to, but once you get familiar with the workflow I don't think you want to miss out anymore. At least I don't. Eventually that gap got filled up by Maschine and once I had that setup I no longer had to rely on Reasons sequencer, the Maschine (hardware) controller made that transition even easier for me (
a lot easier). As such the RRP became a very useful alternative for my setup. Especially after we had more MIDI routing options.
But there's still a bit more to this story... See... Maschine is developed by the same company which produced Komplete; an extremely extensive collection of instruments and effects where sound quality is most definitely a very major aspect of things. In my opinion Reason has always been about sound diversity whereas Komplete focusses more on sound quality.
Don't get me wrong there! I am
not trying to insinuate that Reason has a poor sound quality,
far from it even. There's a good reason why I have every instrument and rack extension made by the (former) Props (and a lot more!). But when talking about realism... Reason has an orchestral soundbank (the "Orkester sounds"). I really enjoy working with that setup, but it is with all due respect when I say that it simply cannot compete with Native Instruments' Symphony series. And this is honestly saying nothing negative about Reason mind you... I hold the same opinion about Ableton's Orchestral Instrument Collection ("OIC"), even though the OIC was the main reason why I upgraded to Ableton Live 9 back in the day. So: the inclusion of the OIC; now I could get my hands on a collection sold for over E 700,- for a fraction of the price.
No, my point here is that Reason provides instruments and effects which take sound creation to whole different levels. Think for example "Note Echo", "Dual Arpeggio" and/or "Beatmap". Not to mention the massive synth potential of powerhouses like Thor, Grain, Malström and my personal favorite: Komplex! I've played Komplete's Absynth 5 (and other synths) using a Reason combo of 'Note Echo' + 'Dual Arpeggio', "glued" together using Live, and then you get into some really extensive and impressive setups!
And don't get me started on those cables
Of course the only "problem" for the former Props is that I'm not too sure about upgrading Reason any longer, let alone getting more rack extensions (my last purchase was Friktion, I love that critter, but even so... I also have alternatives). These days I'm relying
a lot more on Maschine (powered by Komplete) than the RRP. I love Reason's RP for what it is, and it's not going anywhere in my setup, but I don't think R.S. can come up with new instruments or effects which aren't already part of Komplete (which is also fully usable using ("within") Maschine) or "3rd party Komplete compatible instruments". Another issue is that I can control and play all this stuff using my controllers: Push + Maschine, I can create
a lot of sound (effects) these days without ever touching my PC keyboard and/or mouse. You can't really do that with the RRP.
Which is basically my story I guess... TL;DR: A long way of saying that while I've grown to love the RRP for what it is I also expanded in other directions, especially Maschine which compensated for the lack of a 2nd sequencer. That got me involved with Komplete and that opened up another world for me. One in which Reasons RP still has a prominent place, but not as much as Reason 10 (and prior versions) used to have.
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Sorry for the long read but... despite what I mentioned above I'm still quite passionate about Reason, that part has never changed.