It's true, they are a bit less efficient but many people will never notice. Heavier? Are you carrying a set of clothes, tools, lights, maybe rack and pans. Some fenders? Lunch? Heavier seems to be relative. As for less gear range, modern 7 and 8 speed internals have about the same range as a classic 10 speed. It's not quite a triple, but then that's probably ok most of the time.

On the other hand, you don't have to deal with your rear cluster turning into an iceball in the winter, do ya?