Haven' played with the cannon, but from comparing specs, the Nikon has a closer macro focus range by 2 cm (big whoop), and a slightly smaller LCD screen, and can shoot 1/4000th rather than the cannon's 1/1500 (are you really going to shoot at 1/4000? I have yet to find a need for 1/500!). Other than that, they seem to be virtually identical. I like the Nikon, and have a 4300. When I chose mine, I was looking at the 4300 and the Oly 4040. They had almost identical specs also and what it came down to was how did it feel in my hand and the Nikon won. There is something to be said for the small design of the cannon, but I still like the feel of the Nikon coolpix line.
Also, according to digideep.com, the cannon only has the 1 housing from cannon whereas the Nikon has 5-6 housings to choose from depending on how much you want to spend.