Hi,
I was given a variety pack by a friend including a couple of Feathers.

For me the Feather was to sharp and "rough" others love them.

The Crystal was great but the Astra seemed a hair smoother???

Still looking into that, the others I tried were no good to me so dosen't matter!

Have not tried a Shark yet, but I've heard very good things about them!

They are on my short list!

Of course all of these blade critiques was with the Merkur 38C on MY face! YMMV!