I love my 1200C; I'm 6ft and 150lbs, I regularly ride 600+ miles in a day on the stock saddle and I have never had any problems.
The bike fits me like a glove.
I bought the Sportster because it was the bike I wanted, not because of economic constraints.
I chose the custom model because of the forward controls (and all the chrome). I love all Harleys but I wanted something fast and nimble and I find the other models a little cumbersome.
The only thing I would recommend as a must if you are to carry passengers, is a removable sissy bar and maybe, if you are going to have pillions for more than a few hours an alternative seat for the pillion's sake.
I might in the future get a bigger model (ie. Rocker) for the hell of it but I will always keep my Sporty.