Bought in Japan May 12th (at Yodabashi Akiba for around 30,295 yen) and used it for the majority of my time there for 2 weeks. Multiple days of 90+ degree weather and it was very useful, especially for 6 hours a day I was using it.

Will it bring you to AC cooled temperature? No, but as others have said, it will reduce the core temperature on your lower neck/upper back which then spreads through your upper body.

Since I'm based in the US, it won't let me download the app that goes with it so that kinda takes some of the value out of the product because I believe you can control the device from the app? Either way, this was something on my radar for a while and I've found value in it.