Neither would be my first choice and I'd only shop on deep sales/clearance, but if I had to vote it'd be RL because of the fact that he private labels some great pieces from St. Andrews, Caruso, etc.
I just think that you can cherry pick from RLBL and RLPL and get some classic, well made no-logo stuff. All the other diffusion lines seem irrelevant and those lapels on the BL stuff just looks like it is going to scream "dated" in about three years
I grew up on Brooks long before Ralph co-opted them, but the decline in quality has been pretty steep. These days I think of BB as a place for good shoes (Peal), belts, maybe boxers and, in a fit of nostalgia, I just bought two slim fit OCBDs on that 40% sale they had a few weeks back - first BDs in decades! Otherwise, the suits and sportscoats (Greenfield ones notwithstanding) seem to be made by people who crank out license plates the rest of the week.