We had a JLG style where the basket tilt cylinder valve stuck open and dumped tools in the basket. There is still a hard stop...not a carnival ride.
I’ve read several cases from OSHA where guys fell from both man lifts and ladders from an “arc flash” where the fall is what killed them.
If I had to guess I’d say almost every case would involve working off or outside the hand rails or getting knocked off or the unit getting knocked around.
A boom lift is one stick. Riding in one feels like it could go over easily where a scissor lift has 4 point contact so it’s more of a stable ride. But with all the counter weight in a boom lift if it gets hit or hits a hole, you are in for a wild ride like a weeble wobble but there are videos showing those things on a 45 incline and they don’t go over. Plus the stick is designed to be very flexible but very strong. It’s still a stomach churner but you get used to it. Once the “back” legs cross the front “legs” of a scissor lift, you’re going down. All that stability is gone instantly. I can’t say one is “safer” than the other, only that man lifts just feel like they’re going over any minute even on a flat floor until you get used to it. Just look at the wheels and not what your stomach says.