The other wallowed and wandered everywhere and felt like I was going to die at any speed above 40km/h.
This is exactly right. There are SOOOOOO many builds out there that have this problem. They ignore critical issues that need to be addressed that dramatically effect the way the truck handles. They just want it to "FLEX". They have no idea that there is so much more to a properly setup suspension than that. People say, "it's a trail rig so it doesn't matter". It does matter though. They just don't know any better because they've never driven or ridden in something that was build properly.