FWIW - I have that scope in 30hz and think it does a fine job. 300 might be at the far end of its range for consistent DRT shots. It has no problem detecting far beyond that though. In the video, the second group, after I pan left, is at about 300yds+ at native resolution.
I do not have any experience with the 60hz but word on the street is that battery life is substantially less than a 30hz (3 hrs. +/-). If you don't get the external battery pack, your gonna need a whole bunch of CR123's.
Look around and you might be able to find a new Zeus 640-42-30 for not much more than $4K or if your not in a hurry, wait for the new 12 micron core.