There are two types of muzzle brake:
Type 1: These reduce recoil and aid staying on target by trading muzzle jump and recoil for increased muzzle blast and sound.
Type 2: These are often called linear muzzle brakes or Linear Muzzle Compensators and they trade higher recoil for lower muzzle blast and sound by sending them down range. I'm unsure that they improve accuracy by limiting muzzle jump.
Type 1 muzzle brakes were extensively reviewed in 2015 the summary article is
http://precisionrifleblog.com/2015/06/24/muzzle-brakes-field-test/; it includes links to other interesting articles as well.
Type 2 Linear Muzzle Compensators have a number of reviews online but a good comparison between them and Type 1 muzzlebrakes is
http://www.thetruthaboutguns.com/2014/11/jeremy-s/556-muzzle-device-shootout/. I have a KVP™ Linear Comp on my PCC and as the recoil is negligible the slight increase is a good trade for more pleasant shooting. Whether or not it helps with muzzle jump I haven't tested—IMHO that's one component of why I shoot much tighter groups with it than without.
The weight of the gun will have a lot to do with whether or not a type 1 will make a lot of difference. The RPR is heavy enough that I find the 6.5 recoil minor, whether you will benefit more from a type 1 or 2 depends on you, but the KVP type 2 at ~$55 is cheap enough you can try it and if it doesn't work for you then try a highly rated type 1 (note most of them go from $100 up and up). Ive used a couple type 1s on 338 lapua and the barrett in 50 BMG but those are not available for 6.5 creedmoore.