A good write up Rally, great to see that non journalistic comments from Ducati riders can give an open opinion. Your S4RS is something different though, a full on SBK engine in a naked bike is WKD tbh. The SF to me is the same as an S4RS but the Monster is the better bike in that respect. With a 1098 engine in the SF it isn't sold on me, I think its too radicle and hence I prefer the M1100S. I think that Ducati had a better idea with the MTS as an 1198.
Anyway you pays your money and takes your choice, each to their own.