I don't have any recently produced Mk4 scopes; my 2 (6.5-20 and 8.5-25) are probably 10-15 years old. My experience may not be relevant to the newest Mk4HD models.
I prefer the Mk4s over my NXS manufactured in the same timeframe. The glass in the Mk4s is better to my eyes, and the scopes are smaller/lighter. Both of mine are FFP M5 turrets with TMR reticles, which I prefer over the NXS versions. The NXS turrets "feel" better though. I haven't had any issues with the Mk4s, and they've survived 1000s of rounds from various 338 and 375 wildcats.