I can promise you there's no comparison between a Leupold FX1 28mm and a Leupold VX3 40mm. Light gathering ability is kind of a direct function of objective lens diameter. I'm sure it's also a great scope for what it's made for, but as a deer hunting scope on a ML, I think it would leave a little to be desired. I'm all for small fixed power scopes for certain applications, but even then, a bigger objective lens is almost a must. The ultralight scopes just aren't made for big recoil, like you get from a 50cal ML.I would love to let you compare side by side with your 9x. It is so much nicer than any other fixed 4x scope I have used. It gathers plenty of light.