I wouldnt go with the Echo due to the fact that it used factory bottom metal and mags. While this is great for a hunting gun, not Ideal for shooting matches.
The Bravo is the same ergos as the Echo but uses AICS mags, so you can run a 10rnd mag which I know is needed for PRS and Id assume NRL although I havent jumped into that world yet, but I would imagine you would exceed factory mag capacity at some point.
I would recommend the Bravo over the Rokstock due to its modularity, ease of changing length of pull, the ability to add arca rail and weight to the stock if wanted, adjustable cheek riser. In my opinion it is a better choice for a Match Gun.
Ive shot all the KRG chasis and they all manage recoil exceptionally well. I have a braked 20" 6.5 CM in an X Ray, and today I was spotting impacts at 100 yards at 18x as well as 550 yards at 18x. It weighs in right at 11lbs.