We got our hands on the next gen European model, after spending 30-45 minutes or so calibrating brain patterns it was then good to go. For us, obviously we're going to be biased and love the whole thought of brainwave controlled cat ears, it definitely does work quite well from our experience. It's not super sensitive as many people who try to test a reaction of comments to get short term effects but this is something that does work over a short time span of minutes, it is picking up brainwaves, not facial responses or movements. At the end of the day, it does exactly what it says it does and my god you need to see it in person to realise how much fun it is, not just for the person wearing it but for the other people around the wearer!
If you have intentions of wearing them quite a bit (and if you're paying that much for them, why wouldn't you!) it's reccommended you get some rechargables, battery life is around 8-10 hours, so definitely will get you through an entire night of Neko Nation or a convention but it may sputter our and become a bit weaker, slower and noisier near the end of it's time. With that said, it's not exactly like you're going to be wearing it to sleep so the battery life is more than fine and it does use AAA batteries.

Perfection? Well for those who have been excited at the idea there are two downsides, the most obvious one is the price, with headsets costing between $100-195, depending if you get a cheap import or buy locally. So obviously it's better and cheaper to import? Well there's a bit of a gamble, unfortunately the headsets have been a bit hit or miss with a sizeable number of headsets malfunctioning pretty quickly which myself and a fair few others I know have experienced, buying overseas will not get you a warranty under Australian law nor will you get an optimised version for Australia. The malfunctioning has been blamed on poor quality control, with increased pressure to bring out more units due to the insane demand, so I wouldn't be holding out for a price drop soon.
Overall, yes, if you need to have these in your life, by all means, you need to have Necomimi. However with the price and some of the defects going around, this one is for the hardcore fans at the moment. If you want to see these in person, come to one of our events, I generally have them on while DJing! XD