With underwater photography it isn't a matter of if you are going to flood a camera but when you will. It is critical that when sealing the housing a great deal of care must be taken to make sure the seals and sealing areas of the housing are free of any dirt or contamination and just a minimal amount of lubricant be used. Without using extreme caution in doing so a leak is nearly guarranteed.
Based on these facts my suggestion for anyone wanting to to pursue underwater photography is to decide your wants and needs. If they are simply a few nice snapshots then the budget gear is a great place to start and the gear is generally more capable than the users. Intova makes great low cost underwater cameras for the beginner or those not looking for more than quick snapshots. You can take their cameras and add their Slave Strobe and improve the color of your snapshots while progressing as an underwater photographer. They also offer filters and a wide angle lense for some of their cameras for further progression you can ad these and maybe a second slave strobe. When all is said and done if you follow these recomendations. You'll be taking some underwater shots that are better than the majority of what your friends could do on land. You have a very capable underwater outfit and You'll have a complete camera outfit that cost less than just the camera and housing offerings from Sea & Sea or Sealife. At that point you can decide if a more advanced camera (and more expensive) really offers you anything you need.
Another company that offers great P&S cameras and their own housings on a budget is Fuji.
I'll check out Intova first
