The 5-20 US is my LEAST favourite S&B "Opticaly" .... It can be quite "milky, hazy at times....its reasonably sharp but glass wise i think its S&B,s 2nd worst scope ( just edging out the 3-27) optically.
My dealer here in Aus got NEW stock of the current 5-25 PM2 revision...he is stunned how...