I have seen Mer being used at auctions. It comes up shiny but doesn't weather as well as Autoglym. I use Autoglym on my Porsche (black) and it comes up a treat and resists muck quite well.
Autoglym is the dogs doodas when it comes to car polish. 7 years ago I gave my mum's old Uno a good wash followed by a coat of autoglym resin polish, it added £200 to the trade in value
Don't get it on textured plastics. They do a remover for it, never tried it, but I got some on a plastic fuel cap once, looked awful, went white.
Don't apply it if it looks like rain, as soon as you get it wet it is a nightmare to get it off.