Harry, it's a tough decision because they're both great bikes. The day I bought my Speedmaster I sat on the America and the Speedy, each about 79 times. :-D And that was after 4 previous trips to drool over them.
I picked the Speedmaster with the help of a friend that knows bikes. He really liked the look of it, especially the blacked out engine. He pointed out the lack of chrome and asked if I wanted to ride it or polish it. Not that there's anything wrong with the chrome on the America, it's just a different look.
You really can't go wrong with either. To me they're more alike than not. Just slightly different versions of the same great idea. Excellent middleweight cruisers! A nice combination of power, styling, handling and price.
Good luck!