Agreed. After MUCH research this time last year, I settled on Zaino as the polish of choice. It is incredibly easy to use, smells better than anything else in the world (really!), and IS economical- the thinner you put it on, the better. It also really layers well which is more than can be said for most detailing products.
That said, it will reveal any scratches, marring or swirls left underneath it's pristine shine. Using Zaino leaves you completely at the mercy of your prep. level. Get rid of those swirls, etc. first, and I can't imagine a better product to work with.
Don't even bother with Z5 for swirl removal- try something more aggressive (depending on your needs, of course) like 3M's SMR, or even DACP.
Z leaves a brilliant shine, but it does lack the depth and warmth of a carnauba shine. Despite what Sal Zaino says, it CAN be topped with a pure carnauba (Meg's #16/26, S100, etc) and looks OUT OF THIS WORLD.
That is from my own newb experience- hope it helps!