Things I liked: After adjustment it holds zero! For about $50, the 5899 and Daisy globe front sight provide a huge improvement over factory sights on a cheap pellet gun such as the Daisy 760. It is useful for informal 10 meter practice or plinking. This is a better way to learn to shoot than fooling around with a cheap scope.
Things I would have changed: Mount should fit a round-top receiver. Increased vertical range adjustment would be helpful. Adjustment detents could be a little more positive. Needs just a little more beef in the mount.
What others should know: For the price, one should expect it to be mostly plastic, but that seems not much of a problem. I had to flatten the receiver on the 760 (also plastic) and epoxy the barrel to the pump cylinder for accuracy - it is ugly but a quick way to stop the barrel from flopping around in the receiver. Also had to lower the front sight to compensate for inadequate height adjustment in the rear.