Yes, Frontline (Merial) is waterproof and Advantage (Bayer) is not. But unless you bath your kitty, it would not matter much. Although, Frontline kills ALL stages of flea life cycle (egg, larva, pupa, adult), Advantage kills only adult fleas, which is prevents the female fleas from laying more eggs. I think Frontline Plus is effective against fleas AND ticks.
For fleas, both are effective if you keep up with your monthly application. Most of us in the profession go for either Frontline or Advantage for fleas. Some of us not impressed with Revolution for flea treatment, but it is good for ear mites. If your cat/dog has heavy infestation, then veterinarians usually give a oral flea medication called Capstar which kills off all the adults immediately, then followed by topical flea prodcuts such as Frontline or Advantage. And you also may have to treat your house because you will be surprised how many 'dormant' flea eggs stays in the carpet waiting for the opportunity to hatch and jump on the animals!!! Fleas can be life threatening to cats and dogs because it can cause anemia...
Frontline and Advantage are safer than those cheap ones because they only stay on the skin layer and not be absorbed systematically in the body. I have seen especially kittens die using OTC flea products... Also, never use any products intended for DOGS ONLY.
Anyway, too much information, huh?
tiramisu, RVT (Registered Veterinary Technician)