I have just queried the two dealers for Electraglide here at Audiogon:
Standard reply is that the floating ground is usual for all Electraglide cables
You have to opt for the ground, and the floating ground cable is better sounding (according to the dealers).
I would have liked to have known about this before ordering the cables. In fact I had pointedly asked one of the dealers about the floating ground and he did not seem to know about it until he asked Scott Hall at Electraglide.
This was after I had made my purchase and received my cables: Fat Man Ks.
With a high current amp and no ground, there is a safety issue, like it or not, particularly at 110 V.
The sound quality issue I honestly do not know. I am unable to make an A/B comparison as all I have are floating ground Electraglides! Theoretically removing the ground can eliminate ground loop problems if you have them. However according to Russ Andrews (one of the original gurus of power cables) this is not an ideal solution. It is better to have a chassis ground and solve the groud loop problem: please look up his free downloadable booklet on power supplies/mains etc at www.russandrews.com