I should have said that a friend in England is a professional underwater photographer and has been for years. He had a lot of incredibly expensive Canon gear, including top-of-the-range housings whose ports alone cost GBP5k!

Yet a couple of years ago he sold it all and changed to Nikon. He said Canon charges too much for specialist lenses, but I don't know if that's the reason. All I know is that just to make the change he paid over GBP50k. He obviously thought it would be worth it. He now has three D3 bodies, two housings, with assorted specialist lenses and lighting systems. He works for National Geographic, Tauchen (German dive magazine) and others.