I personally love many of PB's products. Easy to use (even in the sun), priced right and very good results ( I have used PB's Pro Polish, Polish w/ sealant, Black Hole, Spray and Gloss).
Mother's makes very good OTC products. I like their Reflections line as well.
I have not tried anything from Adams (althought they seem to be really good) and quite honestly I haven't heard of Coats.