The one difference that really matters between the America and Speedmaster is the seating position due to the different handlebars. So, sit on both and let your back decide. Now, if you like the feel of one, but just have to have the look of the other, it is possible to change the bars for a lot less money than you can change the look.
As for the cow, the Triumph is the only motorcycle of this size that I would recommend for a first bike because they are exceptionally well behaved. Far eastern built bikes are mostly made too instable because that makes them more nimble in the hands of a very experienced rider. I wouldn't recommend anything larger than a 400 class commuter bike from Japan or China to start out on.
