I've seen crash damage from both multiple times on track bikes we work on in our shop, and both have held up well in general. Once we had a GB cover completely worn through, but it was a very long high-speed slide on the track.
For the R&G you need to apply silicon to stick them to the covers.
Dont like the GB because i dont like the full cover look of the Clutch cover. (For track maybe they are the best protection)
For me (no track): the CNC racing/Lightech/Binomici have the best look, mounting points (i use the sato sliders) and seem to do the work they need to do.
the 3 look the same and are on my wish list
Friend of mine had GB Racing on his bike when he low-sided at the track and they held up very well. So I put the same on mine. I don't care how they look - they do the job. Function over form.