I enjoy them. But from what I understand anecdotally, they mess with some people's heads. I use them when Researching or Writing to focus concentration. I also use them sometimes as a sleep aid for insomnia. Although binaural beats are "scientifically' designed, beat trance has probably been a spirtualist practice for as long as people have been able hit one stick against another. I been a part of certain 'shamanistic rites' involving them. I personally find no danger in using them and lots of benefit. They often can jump start a meditation session when I don't have the time or temperment to massage my mind into the right frame. Call it lazy, but hey i've come to terms with it lol.

I-doser sells reliable recordings but make sure you are getting the right recording for the right activity. A mental sharpening recording will do nothing to help you sleep.