Originally Posted by Eclectus

I don't think effort per se means too much, although girls and guys with small hands have reported SRAM works well for them. SRAM is mostly nice because you can shift up and down with two paddles, no need for separate thumb shifters, or using the brake levers. (Campy and Smimano stuff is nice BTW, but SRAM came up with a different idea, and a lot of people dig it) Shimano's Di2, when evolved further, will obviate manual shifting entirely, except for classicists, who like the idea of old-fashioned riding, and doing complete repairs on their own.