I have the 2~8X32 Monarch on a centrfire 30 caliber & love it. Its actually a little better than a comparable Leupold in some minor ways. The lower range models won't be quite that god, but the older 3~9X40 ProStaff I had worked fine as well.
If I really think I can find 2 minor things that might be better, neither of which would stop me buying another one. The turrets are a tad bulky, & bI wish Nikon would actually release the target type turret knobs they've been offering for a long time but never delivering.