Originally Posted by Santaria
I believe its the fact that you have to come out of the drops to downshift (or is it upshift? I'm at work and brain is occupied). All sets above Sora are on the brake level exclusively.
Basically, people don't want to come back up onto the hoods to change gears, which Sora requires with its two lever setup.
I will second that, but only weakly. Generally by the time I'm in the drops, I'm already up into a gear where I'm going to stay for a while, no need to shift. I don't race, and would guess few people with a Sora setup do, so it's not quite as critical to be able to shift while in the drops, and not so much of an actual, as opposed to theoretical hassle to move your hand up if you really want/need to.
There does seem to be an abundance of plastic parts inside the shifters; I suspect the higher-end models use more metal instead. But in and of themselves, Sora shifters definitely get the job done.