All I can say about these primitive screwheads is, “Listen up! This is my boomstick!”
The upside of Phillips is that you don’t need just the right size - the way the slots and the tip are angled means that it’s fairly universal. On the other hand, that’s the exact feature that creates an inclined plane and pushes the tip out of the head.
patents on the original Torx design expired long ago. Textron has come up with several new versions, but the original is clear.
the biggest problem IME is that there’s a T25 and T27 size for some reason, and if you try to use a T25 driver in a T27 screw you’re going to have a bad time.
A screw extractor would also have sufficed if you hadn’t been able to find a clutch head bit. I was faced with a bunch of screws with #0 Robertson heads this weekend. I backed them out in minutes with a screw extractor. I doubt that I would have found a #0 bit locally.
Yes; as others have mentioned, the cam-out feature is there by design. And while it made some sense when it was first implemented, that feature (and users’ indifferent approach to screwdriver sizing) just makes stripped cross-head screws more common than they need to be.
I’ve worked with people who see this as a plus: you can’t overtighten the fastener without stripping it. But you’re still left with a stripped screw head. Besides, torque wrenches exist, and the cam-out feature often means you need an impact driver to remove even an intact cross-head screw. I hate cross-head screws for most applications. They’re better than slotted screws, but so is nearly every other design out there.
The Pozidriv was a pretty good screw head - it had vertical (not angled) walls so that you could torque it pretty good, but the fact that it looked like Phillips had its pros and cons: in a pinch, you could use a Phillips as long as you didn’t need to apply too much torque, but since it looked like Phillips, people would use that and bung up the screw head.
At least with Torx, you pretty much are forced to use the correct driver.