Canon's SD series of cameras are pretty much alike. They all produce the same "clearest, sharpest, nicely color-saturated images under all lighting conditions."

They all have the same engine and firmware. They only differ with megapixels, optical zoom and focal length. You just pick the one with the features you want.

Another difference, any SD camera with a 3.0 inch LCD will not have an optical viewfinder as there is not enough room for it.

Here is a comparison of the cameras you mentioned:

You mentioned "wide angle" but none of the cameras you mentioned have a wide angle lens.