As an electrician, I love my Klein tools. The nut drivers are no exception. Only issue is over the years i've worn the color off the end of the handles of a few. But that doesn't affect performance.
Klein is what I use at work, not because they are something special, but because that's what the local supply houses carry. The screwdrivers and nutdrivers are better than most, but far from the top of the line.