Scope rings

I've used one piece for AR style, two piece for bolt action.
I recently considered a one-piece for a new bolt gun, but decided on two-piece for weight savings in the hunting usage...
 
I use both and am happy with both. The one piece units can be monsters and unnecessary added weight. I don’t mind because they go on rifles that are already heavy. The CZ 22 on the other hand sports 2 piece.