I got one probably 20 years ago, early 2000s for sure, my issue wasn't that it didn't work, my problem was that when following the cadence it was establishing, my speech felt so robotic that I couldn't stand using it. I decided I would rather deal with the stutter and actually sound like me than to be perfectly fluent and not recognize myself speaking. Over time my stutter has gotten much better and now it only pops up under stressful/high anxiety situations.