I've got a set of Hope M4 Evo's which are fairly new, had about 8 rides on them. They don't seem anything special, but are ok in the dry. However in the wet they simply dont work! I was applying the brakes the other day when I'd been through a few puddles etc, got a horrible squeeling noise, bike wouldn't stop at all and I nearly hit a tree!
I've got some black pads in there that came with it. Could that be the problem?
Doesn't matter how wet or muddy the ride, I've never had issues with my X4/X2 combo... Or the Mono Mini's before them for that matter...
I'd suggest you have a pad issue, possible that they're not bedded in correctly (if you believe in that!)
I use sintered pads in the cold & wet, it may be that you've got standard pads that don't take kindly to being cold or covered in grit.
Look at post ref my hope m4s I set me STD pads on fire when they were new,they're mint now!.
I have the non Evo M4's and they work perfectly in the wet/mud. You want to use sintered pads as organics don't get hot enough to work in current conditions.