Originally Posted by EvilV
Seriously though, and racing aside, when you consider the all up weight of a rider and bike, does the odd pound make much difference?
It does, if it's right on the wheel or if you have to carry it up and down stairs.
Long story short is that an internal hub will be a little heavier, a little less efficient, and generally more robust than a derailleur setup. I'm not sure why you'd need to know anything else....