The screwdriver I reach for first is Facom's Ergotwist. Unlike Garage Mahal, I have small hands yet the Ergotwist still feels perfect

. The enlarged ball shape on the end of the handle is great for preventing cam-out when cupping it with the palm of your hands while using the other hand to rotate the screwdriver. The squared profile directly below the ball is large enough to generate a good deal of torque without slippage or discomfort from the hands. The tips of the Ergotwist also fit better in a greater number of fasteners then the other brands I own.
I also like Felo's Ergonic screwdrivers. The handles are
very very soft and squishy

. I can squeeze the handles as hard as I can and feel no discomfort at all! The handle is slightly smaller than average, but the bolster gives you the option to use a wrench to really lay down some serious rotational force. The Ergonic drivers are also prime candidates for those who work in the cooler weather too. I work at an Ice rink where it is 20-40* year round, and these drivers have been very forgiving on my hands
Toptul's screwdrivers are also great in terms of ergonomics and fit. In my opinion they rank right up there with the other brands others and I have mentioned. They come in a variety of sizes (shaft length, tip size, etc.) and wont break the bank either. Given their fit, finish, and price... I think they have the best price to performance ratio.
Here is a review I wrote about Toptul's screwdrivers.