I don't really care about release valves or sapphire bezel, I buy things that I can use without feeling bad about them getting scratched, lost or whatnot... To impress chicks when on holiday I can rent a nice car and have fun with it
Casio G-Shock. Cheap, works good, will go deeper than you will.
And you can spend the hundreds you save on some hot chick. I promise, she'll dig THAT more.