I just thought I would post this in here for a quick answer.  I am looking at purchasing a scope for my new Remington 700VS that I am planning on tricking out.  What I have come down to is this.  

The M1 (52128) Long Range 3.5-10x40, M1 Target Knobs, 30mm tube, Mil-Dot, Side Focus for $749

Or

The Vari-XIII (51668) Long Range 4.5-14x50, Target Knobs, 30mm Tube, Mil-Dot, Side Focus for $699

The only difference I can find is that the M1 has M1 target knobs and the Vari-X has more power and a bigger objective.  Are the ruggedness and quality of optics the same?  Can I add target knobs to the Vari-X later?

Thanks Guys

The LR uses the same M1 target knobs as the Mark 4 and made to withstand exposure without turret covers. IIRC the non-M1 knobs are skinnier in profile and turret covers should be used.

If you really want the M1 knobs I would just get the 3.5-10 because Leopold charges an arm and a leg to install custom mods. About 6 years ago a standard target knob install was $75 and is undoubtedly more expensive now.

Actually checked on this just last week for a Vari-X III. They charge around $80 including shipping with a 7 day turn around.

Also checked on getting a mil dot reticule for mine and it was around $140. Harsh. Awesome scope though.

Haven't seen the M1, I can share my experiences and opinions from my Vari-X III.  I put the Long Range Target model on my PSS 6.5-20 x 50mm 30mm tube.  I never really understood buying $700 or $800 on a scope, (before this the closest I came was a $250 Used Unertl 20x about 12 years ago for my Win 52B).   After trying out the Leupold I quickly decided that I will be upgrading optics my VSSF as well..   I was quite impressed with being able to see the .22 cal bullet holes in targets at 300 yards.  So in my opinion its worth every cent.