I hope this is the right forum to post this. I have a Canon A610 digital camera and I am thinking of purchasing the Underwater Housing Unit for the camera. It is priced at approx. $175 based on the few searches that I did. I thought this was a little steep, but perhaps I'm wrong. I would end up using it 2-4 trips a year - primarily snorkeling or just general pool/ocean photos. I'm sick of using the disposable underwater camera as I get just 1-4 good shots in the whole batch. I have several questions.

Does anyone have this particular unit for a A610? If so, any reviews - good/bad?
Any comments in general on purchasing an underwater housing unit for a digital camera - worth it?

Thanks in advance.