I have some thoughts as I just bought an XTR Pro to test back to back with a Cronus BTR, and ended up selling the Cronus and keeping the XTR Pro. I ran the Cronus BTR for probably 4ish years so I was very familiar with it.
While I thought the reticle on the Cronus was a little simpler and easier to read at a quick glance (I preferred the simple dots in the tree on the Cronus to the alternating “up and down” T’s on the SCR2) the SCR2 is still pretty simple to read and is also a bit finer, which I like for small targets. Part of the preference for the Athlon reticle is because I’ve used the Cronus BTR for many years and know the reticle by heart at a quick glance, while I’m still getting used to the SCR2.
The Cronus BTR does have slightly more elevation travel than the XTR Pro (about 32 mils vs 28) but the Cronus BTR very obviously loses some image quality/resolution if you dial within about 6 mils of the elevation limits, while the XTR Pro doesn’t seem to have any noticeable image quality degradation even when dialed within about 2 mils of the elevation limits. The Cronus BTR image doesn’t get horrible in terms of quality when dialed within 6 mils or less of the elevation limits, but you do lose some resolution and for me it was causing eyestrain over longer shooting sessions, so I had to change my mount to something with less cant to leave it about 7.5 mils up from the bottom at my zero distance to keep my eyes happy, so in the end I had to give up usable elevation travel on the Cronus to keep my eyes happy.
Things I prefer/like on the XTR Pro in comparison to the Cronus BTR:
Glass on XTR Pro slightly better
Larger elevation turret has wider spaced hash marks and is easier to read, plus choice of 2 turrets.
Parallax 5y closer (20y vs 25y)
Much wider FOV at same magnification (24.06 degrees apparent FOV in XTR Pro, 21.2 degrees in the Cronus BTR) – very obvious when looking through them side by side.
Turrets feel more positive (keep in mind I had a Cronus BTR Gen 1, not Gen 2, and the Gen 2 has the stainless turrets with sharper detents.)
After using the XTR Pro for about a month now, if you can get both the Cronus BTR and XTR Pro on Expert Voice for the LE/Mil/First Responder price, I think the XTR Pro is worth the premium over the Cronus BTR simply for the better glass, wider FOV, and more readable elevation turret. However, given the value that either of them represent at that price range I would be very happy using either of them for the price paid. I was very happy with my Cronus BTR for several years, and I’m very happy with the XTR Pro.
I also have an XTR3i 3-18 on my 10/22, and like it as well… very decent glass, decent turrets, etc. My only real gripe is when the scope is dialed near the ends of the elevation travel range (which mine is at zero) it’s very sensitive to head position to maintain a fully in focus image. If you move your head just a little bit you start getting lots of edge distortion and weird image effects. The scope is much more forgiving about eye position when dialed closer to the center of its elevation range.
While none of them are perfect, I think both the XTR3 and Cronus BTR are all great scopes for the price and you get a lot of scope for the money, especially if you can purchase at the LE/Mil/First Responder price. This forum may trend differently in terms of spending habits which can skew your viewpoint but a lot more $1000-1500 scopes get sold than $2500-4500 scopes; if you don't want to spend $2500-3000+ on a scope and instead keep things around $1000-1500 the XTR3/Pro and Cronus BTR would be some of the best choices in that price range, which is probably why you see them being recommended so much.