I wouldn’t venture to guess technical differences in glass composition and/or coatings, but the optical platform is obviously considerably different than the M5Xi (5x vs. 7x mag range).
That being said, I always thought that the main disadvantage of the M5 was its glass. It’s not bad by any means but that design/product is a little dated at this point. I would put it on par with Razor Gen 2s, Kahles 6-24 (not 5-25), and similar. I’ve spent a fair amount of time behind all of these optics and am confident that most would share this same opinion.
The difference is immediately apparent looking through the M7Xi. Whether it’s because of the new optical chassis, the glass, coatings, etc. or a combination of factors, you can definitely tell that the new scope is in a different world as far as IQ goes. As I said before, this is largely subjective as everyone’s eyes see/react differently, however I’m also confident that people who have the opportunity to look through both will be able to tell a considerable difference.
When you get into this price range, I tend to believe that everything is a little “nit-picky,” and rightfully so for how much $$$ we shell out for these new optics. But so far, this M7Xi has not left anything to be desired as far as I’m concerned, especially with regards to the turrets and glass quality.
Thanks browsing, that's what I was hoping to hear. I've a similar opinion of the M5Xi, having owned 2 25X's and currently a older 16X. The 16X is noticeably better, was hoping the new models were at least the same or better than my model. Time to save up my money.