I started playing PVP after 6.1 update and in that time I've ONLY played RPR and what I have to say about it is:

It feels like its a Pressure Class, if you're able to keep the pressure going with your Crest, Harvest Moon and Recup abilities you'll be able to survive a long time in 1v1's even against Tanks or DRG's. You'll have MORE than enough time to build Soul Reaver stacks. The issue I see with RPR's (the VERY few i see and even get to duel) is that people back off or run a lot. Don't be scared to keep attacking. Usually that pressure makes the other person want to run away giving you the advantage in chasing or at least make them go defensive. Plus you have Harvest Moon (which you can throw) to pick up that HP if they get far enough. Now ones of the issues I run into is IF the other person is keeping track of your CD's for Crest & Warrant or by denying you the DMG you would ramp up or shielding on your LB, Warrant Burst combo. Course that being said, you cant just Ogga Booga buttons, you gotta watch your own health too there is a lot of classes that kill you way quicker than you can if you dont keep your HP up. TBH the main focus for me when fighting isn't their actual HP bar, I want to wear out their MP bar so I can get the chance to kill, if that makes sense. Unlike other classes that try to set up CD's to down you in one combo.

But in CC while things are ideally the same, wear down and pressure, there's things that can stop you from doing that:
The first thing is of course them knocking you out before you get to do anything cause they know that downing you starts your stacks over or you rushing/chasing at bad times. (Blame the bloodlust)
The second is your team not being aggressive enough to get you ramped up & going. I've notice a lot of times when I lose (pushing my own mistakes aside) it can be because my team isn't aggressive enough for me to get stacks from assisting them cause they run away to heal up which I understand sometimes, or getting HP low enough to heal decently while Crest is down (bonus points if you get a group of low HP enemies) thus clipping your wings before you even get off the ground. But in CC things can get pretty complicated so kind of hard to say things about it, has a RPR I feel like we have the obligation to adapt to our team comps, since we are not the ones that are dropping enemies quickly by ourselves.

There is ALOT more to it but I am not trying to type a thesis I didn't even mention the LB much. Honestly I believe that in its current state, RPR is a great class, IF you know how to really take advantage of its sustain abilities overall. It took me a while before it just kind of...clicked. That being said, you aren't gonna be rolling heads or anything, and if you're chasing a kill counter THIS IS NOT THE CLASS. Reapers shine from the shadows helping the team kill marks that, if not with your pressure, would of gotten away.

PS. RPR's please duel me.