Dave,
I've just bought this camera. I got it from http://www.uwdigitalcamera.com/ here, I got caught out by the tax man, and paid approx £530 for it by the time I'd paid tax etc, it all depends on the exchange rate you get, I also know that some people I spoke to were more lucky than me with the tax man. I was impressed by the speed of service and would happily recommend him. Everywhere that I looked apart from Cameras Underwater don't include the battery and charger, I got some from ebay pretty cheap.
I've only used the camera above water at the moment and so far I really like it. I looked at the G9 and came very choosing that instead, but I knew that I'd want to add on a wide angle lens, which for the G9 means that you need the Ikelite housing and short port, this makes that more expensive than the DX-1G. I also was attracted by the GX-1G's 24mm lens which I find very useful. Another thing that swayed me was that the wide angle lens you can add underwater can also be used on land.
Just some things you might want to think about!
Carly