You won't hear anything bad about internal gears from me. My current commuter has derailleurs, but I did shop for a bike with internal gears. What put me off was the price. At least around here, you'll pay a premium of a couple hundred bucks for the internal gears, and I wasn't prepared to spend that on a bike that will be exposed to the hazards of outdoor parking in New York City.

The big advantage, to my mind, is that internal gears are clean, and allow you to run a chain guard. If you have to ride to work in your work clothes, and your work clothes are anything other than jeans or shorts, a chain guard is a big plus.

While we're on the subject, does anyone have any idea if anyone makes a chain guard that can be adapted to a derailleur bike with a triple crank?