I recently acquired my first ZCO scope. I opted for the 420 with the MPCT3X reticle. I recently wrote a user review of the TT 5-25 in which, to much controversy, I found the TT to be not particularly impressive for $5-6k in comparison to my collection of Nightforce scopes. I'm pleased to report that my impression of the ZCO scope is very positive. What is immediately apparent is the very robust construction and general feeling of solidity. To me it feels like the rifle scope version of a Mercedes W124. At this level you expect good glass and this scope has it. The 36mm main tube undoubtedly contributes to the crisp, clear optics, and helps this scope compare favorably to larger scopes with 56mm objectives. I'm anxious to look through a 527. The MPCT3X reticle is excellent, but it will take a bit of getting used to as I have become quite accustomed to the excellent Nightforce Mil-XT reticle. ZCO provides a full sized illustration that is very helpful when familiarizing yourself with the unique features of the reticle. One standout feature of the ZCO that both the TT and the Nightforce scopes lack is the daytime visible reticle illumination. This feature really helps to highlight the very thin reticle and makes it usable in situations that otherwise might make it rather difficult to see. This would have made a significant difference with the Gen 3 XR reticle in the TT. ZCO, like Nightforce, gives approximate range numbers on the parallax adjustment. I greatly prefer this to the more basic icon on the TT. The feel and resistance on the parallax knob is just right. Unfortunately, the illumination adjustment has a slightly coarse, unrefined feel. I definitely prefer this style of illumination activation to the ATACR button. Like the Nightforce and unlike the TT, the markings on the elevation and windage turrets are large and clear. The turret adjustment feel is very positive and compares favorably to the excellent TT. The design of the standard locking turrets makes them easy to use even if you don't want or need them to lock. The non- rotating ocular magnification adjustment feels perfectly weighted and the protruding fin, which I first encountered on the Trijicon VCOG, is very helpful and obviates the need for an add-on lever. The diopter locking ring has the ZCO trademark knurling and is easy to firmly lock. One nit to pick; for a scope in this price range, the optional scope caps and sunshade should be included. Overall, I am very impressed with this scope and would have no hesitation in recommending it.