I don't think these are proper terms. You have wideangle lenses, frame filling fisheyes, and circular fisheyes, that leave a circle in the middle of a frame.
The best, in my opinion is a WA lens, much more functional, however if you are set on a fisheye, go with frame fulling, res on digital bodies wont be enough to get a usable image.
A wide angle fisheye isn't a fisheye because straight lines stay straight(if you're using a good wide angle), versus being extremely(and purposefully) distorted with a true fisheye.
All depends on the effect you're looking for, fisheyes are great for creativity. Wide angles have their place too. What do you want to achieve, is the question
i have the 10.5 which is a fun lens, it is the widest angle you can get since it shoots 180 degrees.....you get yourself in the shots if you arent careful
the Nikon 10.5mm fisheye produces a 180 deg rectangular image, not a circular image. As far as which is better depends on what you want. I think most people may find a rectangular fisheye more useful, though you may still need software such as DxO to "flatten" out the image for you. Otherwise the image has a tremendous barrel effect. The 10.5mm may not be as useful as Nikon's 10-24mm wide angle zoom.