I bought this mic holder to use with various different microphone sizes (Shure SM57, SM57, Sennheiser MD441, PG, ...).
Pros:
You can use this holder for various microphones (if you didn't have this type of holder, you would need to change holders if you would need different microphones).
Cons:
Spring holding 2 sides of holder together should be a bit stronger, to have more firmly tight on microphone and to prevent it from falling down.tgo