Cool, that helps a whole lot. I was having issues with trying to picture match, LOL.
Read several reviews online. They were pretty much all positive. If you have a scope with the proper parts and in good shape (Midway apparently shipped some broken scopes to people, LOL), then folks are very happy. As you noted, it is large. After seeing the AR15 image here, it looks like you mount the AR15 to it and not vice versa, LOL. It would be appropriate sized on a Barrett M82A1, though I don't know if it is rated for the recoil.
Users seem impressed with its capabilities.