I commute, so rain riding is just part of the gig. I either use waterproof goretex riding gear in the cool seasons, or Frogg Toggs over mesh in the summer. If your helmet leaks, you got a poorly made helmet. That's where the $$ comes in, honestly, comfort and design...not safety. They're all pretty safe, but a cheap lid fogs, leaks, sweats your head, etc. And, if it's raining hard enough, for long enough, it doesn't matter what you're wearing, you're getting wet.