I have to say having one is better than not from personal experience. At one of the Jeep Jamboree's I was running late in getting the Jeep ready, the flexy pipe running to my snorkel was damaged from the front wheel hitting it and I had not fixed it prior and then promptly forgot about it.
I'm sire there a few people on here that will remember me driving into a deep watery mud hole and taking a gulp of water into the airbox. I was fortunate enough to shut it down fast.
It took hours in camp to pull everything off, and mop up all the water out of the intake and cylinders, but she lived to fight another day.
