I've probably tried dozen or so different waxes (Mother's, couple different kinds of Turtlewax, Nufinish, etc) and my favorite is Meguiar's Mirror Glaze Yellow Wax 26 (paste). I haven't tried Zaino yet, but might in the future. For me, the Mirror Glaze lasts the longest, goes on easy, comes off moderately easy, and no white residue (a big plus on a black car). The Mirror Glaze is a multiple step system (2 or more depending on the paint condition), but the Yellow Wax works well by itself. Meguiar's Gold Class is a pretty good single step wax, but does leave a white residue.
1986 Mustang GT