I was never really a fan of the cartier's in general until I randomly threw on a Santos black leather I had laying around... got more comments on this watch than anything else I have worn. This is the only leather strap watch I have and was the reason I never really wore it, yet as of recently have not taken it off.
Its far lighter (I assume the rubber would be as well) than a traditional steel strap and I have actually gotten real used to it.
Its nice cause the black leather classes up jeans and a polo real well and works with a suit too... as for the rubber I don't know about wearing it with a suit but definitely works otherwise.
Where are you considering purchasing from?