No personal experience with MDM. I've heard some people rave about them and some people rant about them. I get the impression that maybe the owner is someone who has not always had her sh*t together but is trying to gather it.
One thing I really like about Fetching Tags is they are very light for their size, and very durable. Because they are so light I especially like them for when we are on vacation, which is one of the few times I keep all their tags on their collars anymore.
I have ordered a number of tags off Etsy and have been happy with them all:
I like this place because I can get TINY tags. Day to day I rarely have dangly tags on a harness or collar (I mostly use Boomerang collar tags) and when I do I want something small and unobtrusive. The tags came wicked fast and so far are holding up well.
http://www.etsy.com/shop/LittleBlueFoxDesigns
I have also been happy with this place; again the tags came super fast and are holding up well.
http://www.etsy.com/shop/theCopperPoppy
I ordered several from a shop that doesn't seem to exist anymore, called The Happy Chihuahua. Theirs are really cute, that's too bad.