I've been using one each on my G500 and S600 for over a year and a half now hoosier, and I think they're great.
http://www.scubaboard.com/showthread.php?t=60354
Post an UW picture of you in action exhaling when you get a chance too hoosier . . . let's see that standard Euro panache (hmm - does "ugly" from Europe mean "ultra-modern, futuristic" in the US, reversing the translation in this thread?).
http://www.scubaboard.com/showthread.php?t=122066&page=2
It's a shame these bubble deflectors are now discontinued evidently - I was thinking of getting another 1 or 2 and experimenting with a Dremel tool and my wife's talents for patience and skill to modify one to fit a D400 / D350 / D300. I figured I'd need two - one to experiement with, and one to implement the (optimal i.e. correct) result of the experiment. The first piece would have a bit of a Frankenstein look at the end of the experiment I fear.
I can't believe Scubapro kept that crummy design octopus keeper in their offerings instead of discontinuing that item in favor of the bubble deflector. Probably sold more of the octopus keeper since they offered it in more markets, and some executive or committee chose not to weigh in the limited number of markets Scubapro offered the bubble deflector in when they reviewed sales figures and decided to evidently drop it.
Maybe TUSA will pick it up and offer it instead now . . . we can only hope!