We have the Landing Gear and the Stow & Go.
The Landing gear is a small modification and makes a big difference in how stable the stairs feel.
The Stow & Go is very concenient as you no longer need to fiddle around with the somewhat heavy stairs on each stop, and you have a place to store them while driving. At least that was the case for us. But you need a suitably stable place to mount the S&G.
The stairs are great as they are, don't get me wrong. For the first 10 years we were happy with the basic stair set.
They may require lubrication after some time.
You can always add an extra step. We have four, and sometimes that is just barely enough. I think TL provide a measuring guide on their webpage.
As many good things, they are not cheap, unfortunately.