Whitfield recently asked for an update on the Speed Twin (I just now saw it.) I've had the bike for about ten months now, and I've put six thousand miles on it. There's a limited number of aftermarket accessories available (many unneeded or strictly cosmetic) but I have added a couple. I installed Hepco and Becker C-Bow saddlebag mounts and soft bags, and a Dart flyscreen. I also wired in a Garmin harness for my Zumo GPS, with a mount on the left handlebar.
The bike has good power, and it comes on smoothly. Handling is good, despite rather basic suspension components. (I'll upgrade them after they start to wear out.) Ergonomics are excellent for my six foot and 300 pound frame, although the seat gets a bit less comfy after a couple hundred miles.
The Speed Twin has become my "just go for a ride" bike; lunch or a couple hundred miles to nowhere. The ST1300 still handles touring, and the XR remains good stupid fun. The KLR and CL350 still get miles, too, but not as many as before. The Speed Twin is probably the only bike I've ever owned that was "right" right out of the box. It reminds me of when "standard" motorcycles were standard.