I tried it twice, with 2 different practitioners.
Personally, I thought it was...kinda dumb.
I just sat there in a chair in their office with and eye mask on and headphones on listening to metronome beeps whilst holding a cylinder in each hand that vibrated in time to the beeps. Neither psychologists really interacted with me much and definitely didn't ask me any questions whilst I was doing it. For all I knew they were playing on their phones whilst I was just sitting there being beeped at.
At the end of the sessions I didn't notice any change - not better, not worse.
After a few of the sessions though I did begin to feel a bit angry because these were costing me (and Medicare) around $270 a session! And, if they weren't going to talk to me or ask me questions, it truly felt like I could find an app or website an do this from home. So I did. Hell, I even thought I would look into buying a $10 RaspberryPi mini computer and bunch of electronic bits and pieces from Jaycar and building the machine myself, putting the plans up online for people to use for free.
Look, I'm sure the science is pretty solid with some of this stuff, but it's not right to charge someone who is unwell hundreds of dollars for doing so little - ie sitting in a chair whilst in the same room as someone listening to a glorified metronome.
Personally, I've had more success with a homemade Dreammachine (a kind of lamp and rotating shade with holes cut into it that produces a mild flickering light that helps users enter a calming hypnogogic state - which they are looking into doing alongside EMDR anyway). It was very, very calming.
But hey, this is just my opinion/experience.
I hope yours improves if you decide to continue with it.