While I don't deal much with dovetail mounts anymore, when I do it's much easier having the right tools. The ring wrench is kind of a no-brainer for installing rings - not really necessary, but certainly makes the job easier and keeps me from scratching things up.
Pros: relatively cheap & useful
Cons: probably not a 'must have' piece of equipment
This review was written in the old system and had content requirements that are different than reviews written today.