My understanding from past threads was that the Roadster specs were better on paper than in reality. Captains who had ridden both felt that the standard/classic models had more power than the manner in which the Roadster was tuned. Of course that can all be fixed in any event if it is true.
Peg position would be the big one for me. If you prefer more of a standard position then I would definitely go Roadster. But if you like the slightly feet forward cruiser style stick with what you have. Sounds you are a fan of the newer peg position. Also, footboards versus pegs. I think, although I could be wrong, you get a little better clearance in the corners with the boards as opposed to the pegs.
ABS, nicer gauges (although still inaccurate fuel gauge) are all gravy although ABS would be nice I think.
Personally, I do not like the look of the 2 cannons on the Roadster but exhaust can also be changed.