I've heard great things about Wolfgang and McKee's coatings, but I can say firsthand that PBL coatings are incredibly simple and forgiving.
Any residue(a.k.a high spots)buff off very easily with a good MF towel. Just make sure to use many lights and look from all angles so you don't miss any.
Gloss is really good, even on white.

That picture was taken after sundown, and in a rush. The gloss really was super deep and glassy. The wheels and glass were also coated with PBL coatings.
The most important thing when it comes to coatings is the prep work.
Thorough wash, decontamination(mechanical, i.e. clay bar or substitute, and optionally an additional chemical step, i.e. an iron remover), any necessary or desired paint correction and polishing(coatings don't fill, any and all imperfections will be 'sealed-in'.
Then, make sure to use a coating prep product. I would recommend the synergistic prep product(whether a polish or spray)just to eliminate another variable. This step is crucial as coatings need a totally naked and clean surface to bond to.
Then apply the coating, wait the recommended time until it 'flashes' and check for any high spots.
After application make sure to wait the manufacturer recommended time for the coating to cure before getting it wet or washing it.
Hope that helps!:dblthumb2: