Stewart,
Well, as you can see, lots of opinions and choices. There's things to consider here. First, what's going to the main purposes of the ladder? Second, and this may be the guidance for the style/type/size of the ladder you choose, what kind of space are you going to take up with it? Where's it going to be stored?
There are lots of choices out there. Winne and Itasca offered as an option, the 6' fold up version. It folds to about 4.5"x4.5"x6'. I think it's been shown so far. We have a specific spot for it and it's even enclosed to protect it. But, the point is, it's a sturdy, easy to store, comfortable to use, light and compact. And, I've used it for many applications while out traveling. I absolutely hate carrying anything on the outside ladder and never, never will. So, this ladder is tall enough for me to do the important stuff while traveling.
Things like, getting to the top of the windshield for cleaning, and, even the top of the rest of the windows too. Not to mention, since our coach ladder does not go all the way down, it aids in getting to the first few rungs of it too. So, figure out what you'd want to do with it, where it's going to go, what kind of space it's going to take up and, go out and try a few if you're undecided. See what strikes your fancy.
Scott