i have a pair Dev, warm, dry & comfortable but there is NO grip on wet days.
when i'd had them a while i rang up the seller and asked which was best Haix boot, Montana or K2? he said Montana blah blah (more expensive)
i then told him about the grip and he admitted theyd had complaints from others!!
i bought the K2 and fing them great, a shorter boot but great grip and still dry etc.
i dont do stacks of digging mind