I've never seen the advantage to being able to see a level from the drivers seat. You've got to get out to place blocks anyway, then get back in the truck an pull up on them. That big pinbox level is just another big ugly wart IMO.
I'm completely happy with the small levels on the side and front of the body. I position the rig where I want it. Get out, look at level and instantly know how many blocks I'm going to need. Place those, pull forward or backward 1 foot to get up on the blocks. Done!
The small level will stay accurate, IF you were level when you mounted them, AND if you use screws to mount. They come with adhesive tape, but that won't last by itself.