I’ve had a 2 bike pendle tow bar/wheel trough for 8 years or so and have found it great to use – highly recommended.
The tow ball mount is very sturdy. Just grease the two poles a bit and it will slide in snugly with no play.
The wheel troughs are adjusted with allen key bolts on the underside which can rust so they make adjustments a bit of a pain if not impossible but its only an issue if you’re transporting different bikes with different wheelbases all the time so its not a real world problem.
I think the rack is well engineered and sturdy but I’ve not used anything else so can’t compare
that said, a 4 bike rack may be different kettle of fish