There were issues with the most common one, found at Camping World and other retailers. Consumer Reports I believe revealed a few years ago that they weren't happy with it.
Those difficulties may have since been resolved, but I like my folding step ladder, Camping World #20317 online. We've had ours for about 20 years, and originally used it in the house before we got a coach big enough to store it in. If I had to do it all over again, however, I'd get the 7 foot model so it was a bit easier to use to clean the top of my windshield and check/clean the running lights above it. The only other glitch is that the red inserts that act as feet for the two narrowest legs tend to push up into their tubes in time, and aren't easily replaceable. That's not been a deal-killer, since the ladder still works pretty much as intended. The models that have steps on two sides have wide legs all around, and likely won't exhibit the problem. And I like the stability of the 4-point legs. I wouldn't pay the extra money for the model with steps on both sides; you can only climb one side at a time anyway, plus you don't need the extra weight of the larger models.
The telescoping type depends on level ground and something to lean it against at the top, which limit's its usefulness. When our main awning swung open on Canada 1 last summer, a telescoping ladder would have been next to useless on sloping ground along side the freeway, 10+ feet away from the coach side, and well over my head; especially when it came to hand-rolling the canvas back onto the tube, up in the air - I couldn't have leaned a telescoping one against the roller to do that. The free-standing option of mine was a huge plus, and a game changer in that emergency.
Just my 2 cents.
Joel