For my CZ 550 I use Talley quick release rings.
For my multiple Encore and Contender barrels I usually get the bases and rings from Fox Ridge Outfitters.
For Encore barrels or other rifles that have iron sites on that I'm not going to put a quick release scope mount, I like see through Kwik Sites that allow me to still use the iron sites. These came in handy last week on a ground hog at close range making a dash for his hole under my porch; my 30/06 ruined his day.
I tried Leupold quick release mounts on an Encore in 375 H&H Mag. once. They shot loose in short order. I've never had any type of problems with other scope rings/bases as long as I tighten the screws properly and use Loctite where appropriate.