Hi Tom,
Another 1100 owner here. I've had mine for seven years, covered just shy of sixty thousand miles on it, and had few problems.
I did have some 'fun' with the injectors. It was running a little rough for a while, then started playing up while I was out one day; wouldn't run above 3000 revs. Turned out the injectors were shot. Got new ones fitted, still had problems for a year, took it back and they replaced one of the new injectors, no problems since.
Gearbox problem. Owing to me being a prat and breaking the original, I had to fit a recon box six years back. I'd had it on about six months when it started making strange noises. It's been sounding like a box of spanners since, but it's still going, in spite of a metal-flake colour scheme in the oil when I change it.
Left hand heated grip has gone twice. Don't know why, when I first got it a fellow owner said that the left hand grips tend to go....
Oh, and on recommendation from a friend, I started running it on the Shell high octane stuff, or other HO stuff when I can't get Shell. Two things I noticed, it stopped the well documented 'surging', and I got a 15% improvement in fuel consumption.
As for comfort for covering miles, I've four times done a day-trip to the Isle of Skye; the longest of these was 740 miles in 14.5 hours. Had to stand up a few times on the way back down the M74, but otherwise no probs, and I could walk when I got off it.
I've ridden the 1150 a couple of times on 3-4 hour rides courtesy of Allan Jefferies. It's a brilliant machine; better than the 1100 I thought, especially as far as looks go; but not that much better that it could justify a change.
Just a few thoughts on mine, not sure how much help they'll be. But as everyone else has said, they're both excellent machines, you'll be grinning like an idiot which ever you eventually choose...
Dave.