I don't own a BFR, but 2 of my FA's are chambered in .50AE, and 1 of those is also retro fitted with an early .500WE cylinder.
I was aware of the potential for bullet creep in a .50 AE revolver, and thus avoided buying one for years. I finally caved in and bought 1 in 2002, figuring that surely I could overcome any reloading problems. I wanted an "elegant" .50, not a super hot rod, since I already owned 2 .475 L's.
I experimented quite a bit, determining immediately that bullet creep was indeed present with heavy loads, and that accuracy suffered accordingly. I talked with a Speer Technical Services man, and confirmed that Speer uses an adhesive on their bullet to hold it in the case longer, information I had also gotten from another source.
To shorten the story, I did arrive at a load that met my power and accuracy objectives, and did not use an adhesive: a 325 gr. Speer JHP @ 1110 fps, using 21 gr. of 2400 and a CCI 350 Magnum primer. That primer is essential in achieving that accuracy and velocity. This load has been published in The Sixgunner several times, and is below those shown in Speer's loading manual.
I picked up my second FA .50AE, used, about 1 year ago, and it also handles this load very well.
The .50AE is not popular in revolvers, and I suspect that's the reason that Magnum Research began trying to move them through CDNN at such low prices a few months ago. BFR's have a good reputation for accuracy, and should be approximately equal to FA's with this load.