Guys - this is a tough question to answer!
It kinda assumes most folks voting have seen all of the brands, which sadly, is unlikely!
I also doubt that many people have just one set of screwdrivers! Looking around - I have sets in metric and inch sizes for a start. Some folks would use an inch size driver on a metric screw slot or vice versa, but on a top end job, I wouldn't!
Secondly, I need different grades of tools! I love my PB Swiss, but would I use them trying to remove a rusty woodscrew? No, I have some old British made Stanley ones for that! Really old drivers get ground down for weird shape screw slots!
Thirdly, some drivers are good in some respects, poor in others. Wera, for example, have good blades (I just love the stainless ones) but the handles won't clean up in greasy environments and the soft inserts just get trashed!
Finally, some styles are more suited to particular jobs than others! PB Swiss are great for working on electrical and cleanish stuff, but once I start working on a vehicle the Snap On seem to win it! Last week I was working on an old lathe and was using my old British made Steadfast screwdrivers. Why, well they're made in inch sizes, but in 1/32 increments, which you need if you're working on BA screws.
So, the answer is that you really can't have too many screwdrivers!