Stability can mean different things to different people.
When I tried the Al screw jacks, I was mostly concerned with front-back, side-side motion. So I tested by shifting my weight front-back, side-side, and there was still motion. BUT jumping up-down wasn't a problem, the jacks (and front stabilizers) worked fine there.
Another thing is the trailer steps. We are way off the ground and have 3 steps sticking out quite a distance. You step on the lowest and the trailer rocks. Less with the jacks but still noticeable. The simplest fix there is to put support under that bottom step. That solves a lot of our stability issues ...