Very nice review! And some great shots on nice animals!
I have a March 2.5x25x52 SFP/MTR-3 that has been hunted heavily, subjected to the elements and bumped around on and ATV for about 5 years. My experiences concerning reliability and performance are quite comparable to yours. I have not experienced ANY issues. IMO, the stand-out feature of my March is its "unique" ability cut through low sun glare/haze, frequently encountered with my first/last light whitetail hunting. I understand that it is a combination of the internal tube coating and lense design.coatings. I recently acquired, and put a season of hunting on a ZCO420, desiring FFP and MIL capability, as well as seeking improved glass (particularly low light clarity/resolution. A bit bulkier due to the 36mm tube, and about a half a pound heavier being the physical differences, IMO, the basic spec difference(s), and the optical quality(superb!), for my requirements did square the cost between the ZCO and the March. I would add that I have rarely, if ever used more then 20X for my +1000 yard shots on game/varmints so my comparison of the two are at 20x magnification or less.
Overall, depending on one's particular requirements, I think either scope is an excellent value for the dollars spent, and will deliver the goods, and I expect to see continued heavy use of both scopes.