Look into Huntertown Arms. They are what most people have been waiting for and their design is genious. What sucks about most the suppressor companies is they are expensive, for the reasons listed above. Huntertown designs are all modular so they can be rebuilt without needing to pay another stamp fee. If I bought one, it's what I would get.
I ordered a Huntertown Guardian 9 about 15 minutes ago, from Adco. It's user-serviceable and also works with .300 Blackout subsonic rounds. It'll be interesting to see how quickly Adco gets the paperwork to me and how long it takes me to get approved and to actually possess the suppressor.