I've been using the Shiden-kai FX XSoft recently, and it's probably my favourite mouse pad to date.
The XY movement feels exactly the same, and it's not some frictionless surface as others have indicated.
Its slower than hard plastic pads.
The initial to constant movements all feel the same to me.
This is the main reason I love this pad so much.
Using it on Air58 hyperglides, and it's very controllable.
I just hope it lasts about 6+ months before having to replace it.