SourceGear Vault works well with our old legacy source control that used to be in Visual SourceSafe. Yeah, I know, that's how old some of our code is.
There's not much to dislike about Vault. It does what I need and more.
We use Vault for non-Git source control. They do have non-distributed source control also. They can handle just about anything.
We have source control history on our code going all the way back to 1996. There's a vast amount of info that can be gleaned from that history.