I've got several 5R Bartleins. They shoot well but I can't tell that they shoot any better than my 4 groove barrels. They copper foul very little so there might be something to the easier to clean claim.
All in all they're no better or no worse as far as I can tell, I wouldn't make a pick one way or the other based upon a barrel being a 5R.
I think the remington barrels are hammer forged which means they're not really 5R. They do seem to have a reputation for shooting better than their standard barrels but that's probably due to remington spending an extra $10 to manufacture them vs. their usual $5 tomato stake they put on standard production rifles. I doubt it's got anything to do with the rifling profile.
