Came to Triumph from Yamaha's (V-Star 650 and V-Star 950). My Yamaha's were excellent machines, but the 650's shaft drive was prone to failure. Mine never failed but I did 2.5 hours of maintenance on the shaft drive system annually to prevent failures. My 950 was so low it couldn't lean in corners.
While both our Speedmasters are still relatively new, neither has required repairs. My 2010 needed a new front tire as it was out of round, but that's about it. Have 9000 km on that bike now. My wife's 2007 (bought new a year ago) has had the tachometer fog up and leave marks on the glass. That will be a warranty replacement.
They don't use any oil, and they are an absolute hoot to ride.
H.