The handle shape is ok. More of a gimmick that doesn't help or hinder.
The material is another matter. Unless you have just washed your hands in acetone, they slip when putting any torque on them. Having a rag handy to wrap around them is a must. This is where a square handle like an SK or Mac shines.
i beg to differ on that point, i work with dirty greasy hands all the time and they make it easier than working with a hard handle screwdriver that takes a lot more grip to keep from slipping imo