So for the past 10 years or so I have been fly fsihing in Hawaii and I have fished on 4 islands and spent a ton of time on Oahu. There are some things that need to be cleared up here.
First, having been in this industry for 20 years, I for a time, tried to send a ton of clients to Nervous Waters, EVERY single one of which came back saying they wouldn't guide them. So gave up trying to help a fellow fly angling business out. This all changed when captains, Coach Duff and Mike Hennessy began trying to run this as a professional, SIGHT CASTING fishery that it is and should be.
To go blind cast here, at Triangle, Hawaii Kai, Hickam (if you can get on it) or Waikiki is doing yourself the largest disservice in the world of fly fishing. That isn't flats fishing, you don't go to the Bahamas, Mexico, Venezuela, Christmas Island or Belize and blind cast to bones, why in the HELL would you do it here? It certainly isn't "Hawaiian Flat Fishing" as I would consider it although I will concede that ignorance is bliss.
At least one of the guides out of Nervous Waters is also guiding illegally by using a boat without a captain's license, let's throw that in the mix as well.
As far as what Hawaii has to offer, I have NEVER seen as large of a bonefish as I have seen here and if you go with a guide from Nervous Waters, you won't see 90% of the fish you are throwing at and most likely not the one or two you might catch accidentally. Plus, the fish in those areas are of OK size, 3-6 pounds with occassionally a larger one but that is not what you should be travelling to Hawaii to target. You should be coming here having earned the right to fish for fish averaging 7-9 on many of the flats not accessible by foot. Don't be impressed with landing a 4 pound bone in Hawaii, those are everywhere in the world and even if you don't hook one, just to see the quantity and size of the bones here is worth the extra dollars for a professionally guided trip.
Having just returned 3 days ago from my 6th trip there in the past year alone, I saw the single largest bonefish I have ever witnessed. Having been within 40 feet of it, my guess is it was in the 45 inch or longer catagory and I would have never even been able to catch a glimpse of this magnificent fish had I relegated myself to being "guided" by these guys at the shop there.
This last trip, I watched a "guide" put a single angler in a spot and he didn't move for 3 hours. That service they are providing is not "guiding", it is simply parking you in a spot and moving you occassionally while they have you launch blind casts into the abyss. Do you want to pay for that?!
I wouldn't spend $50 dollars for that service as you can do the same thing on your own for nothing because you can drive to half of the afore mentioned flats and walk out on to them yourself. If you are serious about this, go with Coach, if not, roll the dice and don't look back but heed the words of saltman, book a guide with a flats boat, only two of them there.