Some years ago I had a cab over, sitting ontop of the engine, van. I was always mindful that if I were to crash into something I would be toast. Same thing with a class A. Did that have any bearing on my choice between a class A & the 5er? Nope. The decision to get a 5er had nothing to do with safety.
In 2009 we lost that 5er in a blow over. Huge gust of wind hit us broadside & tore the 5er right out of the back of the truck & rolled it down an embankment. The truck stayed on the road. We were very shaken but unharmed.
Had we been driving a class A & that same gust had hit it broadside the chances are that it would have gone over too & rolled over that 50' embankment. Given the way they are built above floor level chances of survival would have been slim. But hey, the chances of being in the wrong place at the wrong time like that are very very slim.