AVID disc brake pads - B4

[pszczepan]

Hello !
Some time ago I had B3 Avid pads and they worn out really fast. I heard that newer C-4 are better. Right now I can buy B4 AVid disc brake pads.
Do you have any experience with them? Are they OK, or f.e. Kool stop for Avid is better.

Thanks in advance
Pawel