My vote goes to Weaver split rings.

Weaver split rings don't look at good as some of the rings mentioned above, but when installed properly, they are strong enough to handle all the recoil even the big bores have, and stronger than most!! 99% of my rifles have the Weavers on them, and best of all, they cost less than the "high priced spread".

As for built in ajustment? None of my rifles have needed it!! I would hope a rifle of "decent quality" with a scope of "decent quality" built today wouldn't need it either!!

Drilling Man