I was in your same shooes last year and it was between the S4Rs and the 1098. I tested the S4Rs twice and loved it but kept wanting to ride the 1098 (there were no demo bikes then at my dealership). Was about to get the Monster when a Termi equipped 1098 demo bike was made available.
Wow, not fair, but I fell in love instantly and a week later, bought a 1098S. It was the sound, excellent handling, very good ergos (for my 5'7" size) and power that swayed me over. I use it to commute here in Manhattan (NYC) and its not a problem even when its super hot outside and the coolant temp is at 230degrees! I am having way too much fun on this bike and it was a good decission. I know because when I see an S4RS, I don't even have any remorse or second thoughts about not choosing that bike instead.
In short, you will have to make up your own mind about what you want. What you really want deep inside.