All scopes have a sweet spot right in the center of the objective lens. Some of the scopes that cost $3k ~ $4K aren't going to be that different from edge to edge. Other scopes give you a noticeably degraded image as you peer at target through the edge of your scope's objective lens. A 10 MOA cant to a set of bases or a rail is not very much, although they are available. A 20 MOA cant seems to be a happy medium between the 10 MOA and a 45 MOA cant.