After decades of riding with rim brakes I made the switch over to discs about three months ago and I have to say there is zero chance I'll ever go back to a rim brake. It's not that disc brakes stop better - it's that they stop a LOT better. Way better. And that's in dry conditions - throw some rain into the mix and they're light years apart.
As for weight? Yeah, it's a bit heavier. So my bike weighs 18.5 lbs instead of 18.0 lbs. No biggie.
Rotational weight? Whatever, I'm not a physicist.
Asthetics-wise, I've come to really like the way they look - sexy, even. In fact, bikes without discs are starting to look wrong to me.
5-6 of the guys in my cycling club are running discs now and they've all been saying the same things as me: 1) works better, 2) looks good, 3) better feel, 4) wouldn't go back