If you are off-road a lot then emptying a 5 gallon cassette is a lot easier to do than a 15 gallon holding tank. Any outhouse will do. The cassette will handle about 20 flushes before it needs to be emptied. Hopefully that's more than a day or two but that would depend on how many people are using the camper.
Two or three times raising or lowering a unit by hand will soon convince you that electric jacks would make your life a lot easier.
Both manufacturers have a long reputable history. I can't speak for the Lances but I spent a day at the Northstar factory recently and I learned first-hand how well their units are built to last. Everything in the shell and the interior is fastened multiple times at every contact point. They are rock solid.
And perhaps foremost, Northstar is absolutely number 1 when it comes to customer service.
Whichever way you decide to go, enjoy your camper.