Lets not beat up on the shafty's.

Shafty's have plenty of good points

, hold on let me think

................ oh yeah, it's easier to keep that area around the rear wheel and the wheel clean, and....................they don't require adjustment, and............. well, they normally have bigger gas tanks

. I guess that's all I can think of

.
Chains on the other hand can be messy, leaving all that gear lube on the chain guard, swing arm, sprockets, and wheel. This helps protect that area it covers from rust from exposure to salty roads in spring among other things, and this lube can be cleaned off exposing a like new finish

. You got to like that!

Chains are lighter, less unsprung weight on the rear wheel, that's got to help the suspension in some way, maybe even the handling, especially in a bumpy turn. Chains do require frequent adjustment, I try to adjust mine about every 6 months or so, and put a little 90 weight gear oil on them every 500 miles. Chains lose less horsepower to the rear wheel

. More power to ya, baby!
And although I can't speak from experience, I have read that shaft drive models exhibit torque problems when accelerating and slowing down, tend to make the bike pull to the right or left depending whether you're speeding up or slowing down

.
I guess that's why shafties are more suited for touring, long straight roads at steady speeds and the chain drives are pretty much suited for everything .