Just from my personal experience, I had one of those and while it looks impressive and very cool on the front of the trailer, I sold it at Nashville last years Rally. I went back to the tried and true method of getting the rig on the spot, getting out of the truck and checking my side to side graduated level to see how much I needed to put under the tires. Move the rig a bit, put the boards down, pull up on the boards and set the chocks.
Not that I've traveled the country but there have been very few parks that have level sites and I've had to use boards to level in most Parks. I never knew how thick I needed to use till I got out of the truck so I saw no point in those big fancy looking levels. Another issue with them is you have to protect them from UV. They degrade and eventually leak (long term exposure).
Go to Wally World and get the cheapo graduated level set. Or go to CW and get
one of these for front to back leveling. Best device I ever used.