I do have the 5D MK III and my great lenses. I am VERY happy with it.
Now for travel I am contemplating getting a spare body.
So if I were to buy a 6D or 5D2 it would not fit in the housing if my 5DIII breaks. So I would have to get a spare 5DIII body (Costly)
Or if the worst thing happens and the 5D3 breaks, send it off to the Locale Canon repair center whereever I am traveling in and wait until its repaired. In the meantime use a phone (no underwater photos) or buy a cheap PS camera while I wait for the repair.
Anyone has experience with it and how do you approach it? Thanks