I have a 1st gen Cronus and it is a very nice scope. I really like the reticle's that Athlon offers. The Cronus BTR is a good upgrade over the Cronus,the turret's are better and they changed the reticle size a little.
You get a lot of scope for the money with the Cronus BTR,it'll compare well to scopes costing a lot more. It also falls a little short in some areas when comparing it to scopes like the Nightforce ATACR, S&B PM II,and other scopes in the $3k+ market,but then the Cronus cost 1/2 as much.
My Cronus tracks very good,the turret's are crisp and tactile ( I removed the rubber O-rings on them),the glass and lens coatings are nice to my eyes. It's a pretty nice and well built scope.
I have several high end scopes that I compared mine to,and it doesn't lag far behind them in performance. I also have an Athlon Midas BTR and Ares BTR scope,they have performed great as well.