I've been using Casio G-Shock watches for 10 or more years. I've taken them scuba diving to over 100 feet with no problem. I don't wear a watch when I swim, so I don't know what it would do with daily abuse, but if they don't have a problem at 100 feet, they are decent.
The only Ironman watch he bought died the first time he put it in water. Others seem to have good luck with them though.