Well, I have acutally had/have both brands on my junk. Of course this was a few years ago, so I would only hope both are still building their springs the same.
Hands down, the RE ED 4.5's had a better ride, but in retrospect, not that much. I feel and have always felt the BDS 5 inch springs flexed better and had a better feel in the rough stuff. BTW, running the same shocks, so equal comparison. The ride of the BDS springs was very close to that of the RE's, but I would give the edge to RE. But as an overall general assessment, I prefer the BDS's.
'05 LJR, 6sp, RC long arm w/MC 6" coils, 5.13 D44's w/chromo shafts, MetalCloak fenders/sliders/body armor, 37x12.50 MTR's, Warn 9.5, RockHard swing out w/full spare. <><