Very difficult to say, they are very natural and good on vocals, like any system Derek has had a hand in designing. I owned the Spendor S100s in the past which was a descendent from the original BBC LS5/5 and Derek designed, from memory, the LS5/1 do things on a somewhat grander scale, the 15" woofer really does deliver excellent bass and has slam that the bextrene 12" used in the S100 didn't have.
Interestingly enough, I did own a pair of the original KEF made BBC LS5/1AE system and the Graham version has a larger cabinet with the same footprint but 1140mm high as a floor stander instead of the original as an 850mm high stand mount.
The Graham version certainly had similar and familiar traits to the Original LS5/1 but a thoroughly more modern and dynamic presentation.
Graham LS5/1 had a much more coherent stereo presentation and was just as neutral and has bass extension certainly into the low 20s in room.