I like my Shimano Alfine 8 very much, mainly for the low maintenance it requires (it requires some though), silence and the smoothness of shifting. I like how quickly I can shift to the lowest gear when encountering a hill or sand, etc. I really don't like its weight when I need to carry my bike and I don't like when my chain stretches.

On a derailleur equipped bike you can shift in the rear at the stop light almost as well. Shift the shifter, lock your front brake, lean a bit on the handlebars to raise the rear wheel and push on the pedal to rotate rear wheel and to let the chain move to the right sprocket. Pretty simple: shift, lock, lean, pedal. Not possible to shift to the lowest gear like with IGH, but that's ok, normally I need only a couple of gears lower to start from the intersection.