Sportsters are a dime a dozen. Lot's of after market to make it "fit". Seats, bars, pegs, mirrors, windshields, etc. ebay is your friend in this regard and kijiji can also be helpful. The dealer is super spendy. Maintance is pretty easy if you are a DIY but, a shop manual is neccessary. The Sportster doesn't like to tour very far. Folks do take them on long adventures. Including myself. But, it isn't a fun bike on 400 series highways for very long. You'll get tired buzzing along at 120 + km/h. It's a nice boulevard cruiser and enjoys searching some curves in the back roads travelling slightly above the posted speed limit.
I have a windshield but, it doesn't do much. A taller version would provide the protection I'm looking for but, it looks out of place. Forget about any 2up rides beyond an hour. It's a smaller bike to begin with and the suspension is soft. Aftermarket again is your friend. Your passenger won't be asking for another ride very soon. If the model is a rubber mount engine with the 4.5 gallon tank, it's a bit more comfortable. If it's a solid mount, the vibes can get to you after a full day of riding but, the smaller 3.3 gallon tank means you'll get a break a little more often. I range 200-210 kms when I hit the reserve on two lane black top. I lose a bit of range on 400 seriers as I travel at a higher rate of speed. 185 to 195 kms before hitting reserve. My bike is carbed. 2006 and newer are FI.
I've looked at the America and ridden it a short distance. It's power delievery is very smooth. The ergos felt better. It didn't have a windshield and I never went on the highway so, I can't comment on the touring aspect of the bike. Nor can I comment on the maintence/service or reliability. The stock seat was comfortable but, the pad for a passenger looks best for trips for ice cream than trips to the cottage.
I personally like the Triumph brand and would likely own one sometime down the road. The America has a larger fuel tank. You don't come across them very often so, you are riding something a bit special. It's a toss up for engine sound. Both bring a smile to my face.
I think given the choice, I'd let my butt decide and take them both for a good ride.
If you care about what your peers think or even the general public. Harley owners themselves are great. There are some butt heads that think it's the only brand worth riding but, it's only a few. Non HD riders love to poke fun at HD riders. Ironically I get nothing but respect and positive comments where ever I go. So, if you don't mind the additional time for casual chit chat with strangers at the convenience store or gas station or kids chirping, "Nice bike!". The Sporty just might fit the bill. The conversation usually starts out, "Is that a Harley? My brother/friend/relative has one.........."
Triumph owners seem to get respect from most riders and don't appear to receive any of the negative comments from the peanut gallary. You can hang with the HD folks or any brand or style you want. You'll probably get a lot of the same question. "Is that a Bonnieville?" Triumph bikes certainly have a lot of character. They look good, they feel good and they ride good.
That's my take on it anyways. Maybe a few Triumph owners can chime in?