Are you gonna be dialing constantly, or just for the occasional long shot?
Any chance of the adjustments getting moved or rotated unintentionally?
If you're the "sight in at 100 and dial everything all the time" type, go with the M1.
If you're the "sight in at 300, use a reticle for holdover/windage usually, dial only when needed" type, perhaps the target knobs.
The target type will be covered If I am not mistaken, and less likely to get moved if you are just dialing the scope every once in a while. Although, the M1 knobs on my Mk4 seem fairly stout. I've seen tactical style knobs get moved a full rev out more than once.