I had a R1200C in 2000 and 2001 for about 6,000 miles. It is very much like the America and Speedmasters, all weigh just at 500 lbs and have the same HP give or take a few, the 12C had more torque, 70 lbs/ft and was a bit quicker, the 12C also handled a bit better probably because of the shorter front end rake. The BMW also came with spoke wheels with the same size tires as the Triumphs, but wore tubeless tires thanks to the BMW spoke wheels that have the spokes coming out of the rims outside of the tires (pretty slick design). The BMW required premium fuel and was FI and got around 50 mpg. The 12C did use a bit of oil..about a quart every 1000 miles but that is pretty typical of BMW and goes away around 8-10k miles once broken in.
All that said, the BMW just did not speak to me like a Triumph did. Of course I grew up on Triumphs starting in the 50's and had to come home, so to speak.