I use Leupold, but I am sure there are other good ones.
I may over time convert or go with warne weaver style bases, so I can swap scopes, and I would think they would still be level.
Weaver is the slotted type that use a bar.
One reason would be to be able to put a big scope on for working up loads. I don't do it often, but would be nice to be able to swap scopes and not have to level the rectile ever time.
I suspect this is a debated topic with some.