I have used carnauba-based polish in the past (Zymöl) and still have some kicking around. It gives a very good shine, and doesn't leave white marks, but when I had to get the tailgate of my Cinquecento re-painted (rust bubbling through from the inside and the car was only a couple of years old at the time), when I got it back, the polish had been removed by the paint preparation products and the finish looked absolutely dreadful.
I've tried various potions over the years - Mer, Zymöl, and others I've forgotten about - and it's the easiest to get hold of and with the best range of different kinds of finishes for all the nooks and crannies of your car. The wheel cleaner is particularly effective.
Nick