Hey up Doug
You have to ride both to get the feel for what suits you.
It will be a bit of a culture shock coming from the S3 but neither America nor Speedy should disappoint too much.
I have a '53' America and love it.
I prefer the America riding position over the drag bars of the Speedy.
Speedy front brakes are much better having twin discs upfront.
You could always get the best of both worlds - get an America and do the twin disc front brake upgrade thingy

...then again, I also have an '08 Rocket that I'm just about to go and play on .... vavavoom

BTW, like Grzegorz said, where you at?