My .02... another vote for WRSI. and earplugs. (shameless plug for earplugs. theyre crucial...)
the WRSI full face, nonvented helmet is my next purchase. had one regular vented WRSI since they came out and offered em for $40 or $50 bucks in 2006 . I have had some good hits and its held up fine. And because I wear earplugs, I don't count on hearing well in rapids. got to hopefully use visual cues cause rapids are loud no matter what. I still have about 50% hearing with the cheapy rubber 'xmas tree' earplugs anyhow.
Baer has a good point about vents not blocking the water as well. I havent been pinned too long yet, (knock on wood) and I am not a class V paddler. Class IV mank in NM is plenty pinny at lowwater...(got on the Red, santa cruz, numbers, and upper canyon embudo at 2.5' this year
Also.... theoretically Vents could catch on rock spurs and hurt your neck rather then slide across them. I dont know if thats what happened, but i got a 'stinger' this summer where my head hit unexepectedly as i tucked up to roll, and either it was a hard impact, or my neck was relaxed too much, but it wrenched my neck back and made light flash in my head, although i didnt have any loss of CSM..(sensation) it scared theF#$k out of me, hurt, and my neck was sore for a month. hell its still sore. but i am here to talk about it... so the helmet did its job, and doesn't look much worse for the wear...couple good gouges.
so yeah I recommend WRSI unless they dont fit ya....
or you got top dollar for a sweet helmet.
And Yes I also vote to retire any protective gear that has structural cracks that big.and i wouldnt buy that brand again. and in fact i didn't...after the shred ready scrappy that i had that was as about as good as one of those helmets you used to get ice cream in at baseball games. i.e...not...