We have been using the Ultimate Jack for several years now and are very satisfied. I think you will find that the whole Jack E Up gear is about the same price as the Ultimate Jack.
With the Ultimate Jack you can really adjust to severely unlevel places. The telescoping part allows you to do the gross height adjustment and the screw jack allows fine adjustment for leveling.
We originally bought ours because we found ourselves in a site which required help to lift the tongue off of the ball with the jack fully retracted. On our last trip we had to opposite situation in which, to place the trailer where my roof mounted solar
would work best, we had to park in a fairly severe nose down position. We telescoped the jack down and when it was locked we jacked it up to level. Well chocked and with the outriggers set, trailer was solid as a rock. We camped that way for 2 weeks.
For the flexibility and price, I find it hard to beat.
Installation is simply removal of the old A-frame jack and replace it with Ultimate Jack.