Rather different experiences/opinion here, especially in the functional (protection, durability) diffs with various paint treatments.
IME very few LSPs provide satisfactory protection against etching, which I consider utterly crucial, but the few that do are virtual miracles compared to the also-rans (and also display near-miraculous durability). The OCW I use on my wife`s car provides virtually zero protection against etching (but hey, neither did M16 when it really counted

) and both it and the UQW/D156 need redone quite frequently compared to the LSPs I consider worthwhile. I`ve kind of gotten to where I just redo the Spray Wax almost every time I wash her car, at least on certain areas...easy enough since I always use some Drying Aid anyhow. Looks fine, but it`s not really protected compared to the other vehicles and some day I`ll probably redo it properly like the others.