My 2 cents.
I own a heap of SA Widders. I also own an RER. I can't speak to a GP.
If you have a long draw...go with the Widow. I pull 29 inches and IMNSHO, BW makes without a doubt, the smoothest drawing bow for a given length. I can shoot a 58 inch Widow. I cannot shoot a 58 inch RER.
If you have the need to have a bow that stands out in the crowd, RER will build a bow that will make your eyes pop. BW will build what you want but in terms of flares, saddles etc.... in the riser, RER will provide more options.