Yes, I have been using brainwave entrainment (which is what holosync is) for 6-7 years now. I am also big into meditation and self-hypnosis.
I find it really helps with problem solving, going into a trancelike state allows me to visualize complex problems in ways I cannot in my normal state of mind.
I like the stuff by Dr. Jeffrey Thompson
BTW.. with brainwave entrainment there are different frequencies which are designed to elicit different responses (alpha, beta, delta, etc) so be sure you know which one you are using otherwise it may put you to sleep ; )
i also work with brainwave entrainment + meditation-stuff.
helps me to bring me in a quite + focused state or bring me back to a clear mindset after loosing it - ie after emotional "break-outs" because of whatever (dummy-looser-trade / tech-trouble / trouble-talks / kids-chaos ....)
The brainwave-audio-techniques i found very easy to intergrate in normal day activities - you dont need to greate a special time-out or a kind of a "holy room" - just turn it on while trading or do a session bevor you start - just like your other preparations you have to do.
my goal is to bring me in the best condition for the thing i have to do - a sportsman has to do a warm up before he goes into the match + give his best - i prepare myself also with techniques i know and i trust in.
I have used Holosync for about a year. I am currently useing the second disk of my first customized set. Made a recording with a lady friend so its more attention grabbing than just having my own voice encoded (my theory anyway)