I personally think they are an amazing piece of kit, they effectively "simulate"(key word) the real deal. I have had the pleasure of using Thunder B's and definitely recommend them! Personally I've watched 3 live DD's go of in less then 20ft, yes they are truly loud even car alarms reacted to them

!!! And I have also had these toys go off in the same room as me some no less then 3ft, yes they are slightly loud but by no means even close to the real thing!!!! Thunder B's are also in no way shape or form terrible or un usable/safe or harmful.
This is at the end of the day a toy used to ad realism to a milsim sport

. I personally don't mind them going off or being used against me it adds to the adrenaline/realism and training factor. If your the person who doesn't want realism or to face the noise factor simply throw some 1$ soft plugs in your ears and you will be fine

. If that person is still so against a milsim toy in a milsim environment maybe they should consider the nature of the milsim sport they are playing and pick up a paintball gun. Enough said there.
What people don't realize is these are definitely small in comparison to the real deal,and still small in comparison to what Ive used with the military multiple times for training(for those that know a Tflash). So if they want to play at being an operator/soldier or w/e military like role then they should have no real problems with using these training toys as well. They add to the affect and definitely do give a realistic and practical/tactical advantage to the user!
I would stress to those individuals who don't want realism stop complaining and ruining it for those that do, theirs nothing worse then paying top dollar to attending an Op/Milsim game and some kids or sensitive adults complain about a safe training aid being used. If they are worried buy/bring earplugs or simply attend other events. Also maybe the milsim style of games aren't for those individuals.
Just my 2 cents,
Cheers