I was SO excited when I saw Redfield was putting out a new line of scopes. I have two older redfields, a 3-9 and a 4x. The variable sits on my number 1 deer rifle. This new line redfield came out with is made by Leupold, so you know its gonna be nice. It's weird, Redfield and leupold were competitors for so many years and now they're together. Anyway, I read a review I think in Guns & Ammo last month that was very favorable, and with the price below leupolds rifleman and nikons prostaff, I doubt you can go wrong. Actually, I wouldn't be surprised if they up the price next year after they get some of their product out and get some name recognition.
I havn't shot a 308mx, but if you like lever actions, I havn't heard anything bad about them. I hope you handload though, because the ammo is not everywhere. Personally, for a long range lever I like the savage 99's, but I like the old classics.
Bottom line, I think you'll be VERY happy with that combo. Put some pics and range reports up if you get it!