I have for 2 different dogs, but I ended up both times at a vet with a behavioural specialism instead.
Both were for reactivity/aggression with people. One was caused by pain and a complicated medical background the other is just shitty genetics and a rubbish start to life.
Whether they helped or not is kind of complicated, because neither was really ever going to be resolved tbh, we’re talking quite severe issuses. I can do basic counter conditioning myself and stuff like separation anxiety I wouldn’t go to one for, I’d just get on with it.
So I’m talking about dogs with a bite history who would bite or attempt to bite people just for existing near them, as in the trigger was just them being there not specific things that they’d done or resource guarding or anything a bit less extreme.
The first, we made progress and possibly could have pretty much resolved it if every time we got close he didn’t develop another medical issue 😂 he ended up being PTS at 6yrs old as we could no longer manage his health to keep him comfortable.
The second is one of my current dogs - I got him at 5 months, from a rescue, he was originally from abroad and had never lived in a house or had any training or socialisation, we managed to do everything with him except get him ok with other people ourselves, he’s on fluoxetine now, but it just makes him more manageable the training is still only tiny forwards steps (better than none to be fair) but he’s never going to be a “normal” human social dog.
So possibly not a hugely helpful answer 😂 what issue is it you’re thinking of using one for?