Uhhhh...... *wants to clear up a few things*
Polyester wicks faster than polypropylene, it dries faster than polypropylene, is a better insulator when wet than polypropylene, and stinks less than polypropylene.
Obviously how the fabric is made counts for a lot, but polyester is for all practical purposes a better fiber (for diving as well as skiing, hiking, climbing, etc) than polypro.
High quality fleece (Polartec) is made from polyester.
As other people have pointed out, the temps you're diving in make a big difference. Adding a polyester track suit over some undergarments may or may not help.. if they're thick and add loft, then you will be warmer. If they're thin and add no loft then they will not help.