Of all of those, only PA2X is a touch screen... there are issues there (you'll probably use more force jabbing at a more vertical screen than a flatter one), along with what I suspect MIGHT be durability issues with a motorized mechanism that is going to take a fair pounding over the years. I will feel a lot more comfortable with Korg's new screen after it has shown it's legs for a year or two...

But I think the problem disappears if only the manufacturers recess the lower edge of these screens just a LITTLE bit more (less that 1/2" would make quite a difference) and raising the back edge less that 1/2" too. I just feel for long term reliability and protection, a fixed screen is probably the more durable solution.