We added the 4-point ground control system this year (it was Rico-Titan, but Lippert bought it recently). We're all-electric. This was our first leveling system.
It was billed as an easy DIY project... but we had issues with installing one of the back jacks around the slide-out mechanisms.
Once we had the back jack locations ironed out, it was not a hard install. (DH did it, so it was very easy for me. HA!)
We opted to go behind the slide, still as close as possible to the axle, but more than the recommended 18". We did talk to Lippert's Ground Control support about the location, and they ok'd it from a frame point-of-view. I do worry about hitting the jacks on curbs or speed bumps, but so far, so good. It's only an inch or so lower than the sewer pipe (and closer to the axle), so it really should be fine.
It has been very nice so far.
I love the increased speed of the front jacks, and once the back jacks are firm, there is NO movement in the coach.
So far we haven't trusted using the jacks to take the wheels completely off the ground - one place we park is at least 6" off-level side-to-side - so we still use boards... but we do some fine tuning to level with the ground control, and it's great!
PS - Tweety's had much better pricing than CampingWorld.