A lot depends on what you're looking to shoot. The main difference is that the Tokina 10-17mm is a fisheye lens and the others are rectilinear lenses, which means you're going to get a much wider angle of view with the fisheye. You really can't compare the 10-17 with the 11-16 or 12-24 as they are completely different lenses. In general, using your camera with a dome port, it will likely mean you will get sharper corners with the fisheye than the other lenses (in the absence of any correcting diopters). However, I believe this lens is fairly unique in that it is a zoom fisheye, which I am unaware of any others on the market. As a fisheye though, you're going to get curvy lines closer to the periphery of the frame, but for underwater use, it is definitely less of an issue than using it on land. The other one I would have a look at is the Nikon 10.5mm f/2.8. I believe the Tokina is a f/3.5-4.5 so you will have the edge with the Nikon if you shoot a lot of dark water/low light conditions and really need to open the lens up.