Going back to the technology, the simple claim of brainwave entrainment is that, by listening to these audios, usually with stereo headphones and eyes closed, your brain will be naturally and effortlessly led into a specific brainwave state as designated by the maker of the audio (ie: it could be alpha, theta, delta, gamma, etc., depending on what the audio is designed to do.)  The other most basic claim is that when listening to these audios, the right and left hemispheres of the brain synchronize and you experience whole-brain functioning.
There basically are a few things that you can use to deduce whether you think these claims are true, and will work for you.  A few manufacturers of this type of product have taken the time to hook up experienced meditators (like zen monks) to encephelographs, then fashion their audios to mimic what is occurring in these deep meditators’ brains.  It would make sense then, to a large degree, that you could experience similar benefits from your brain undergoing this process. 
A very pleasurable experience during listening (and often for some time afterwards). As Holosync® changes your brain wave patterns to those of deep meditation, the brain produces several very pleasurable neurochemicals, including endorphins (the same endorphins responsible for “runner’s high”)…as well as several hormones with a profound and positive effect on longevity, aging, stress, and well-being.
With brain wave entrainment technology, changing brain wave states is an instantaneous and effortless process. The 'periodic stimulus' can be sound, vibrations and/or light. We have found that we get the best results with blinking lights which are experienced through closed eyelids. This is only problematic for people with existing diagnosis of photo-induced epilepsy, as blinking lights can induce a seizure in them. The programs are enhanced with Deepak Chopra doing the narration along with holographic sound effects and original music composed and performed by Rudy Tanzi.

In physics, entrainment is the process of two oscillating systems coming to assume the same periodic rhythm, such as is observed when two clocks slowly synchronize their ticking and tick together in harmony after some time. Pendulums also achieve this same synchronicity when swinging in close proximity to one another, a phenomenon first observed and written about in 1665 by Christiaan Huygens, a Dutch scientist.
Hi Sahil, it’s hard for me to speak about other people’s tracks and videos, as I don’t know how they created them either. If you’re interested in a particular track/video and unsure about it, try asking the creator a question or two about the track, what frequencies were used and for how long, what software they used etc. Then make your own judgement based on how they reply to you. Jason
Cvetkovic D, Simpson D, Cosic I (2006). “Influence of sinusoidally modulated visual stimuli at extremely low frequency range on the human EEG activity“. Conference proceedings : … Annual International Conference of the IEEE Engineering in Medicine and Biology Society. IEEE Engineering in Medicine and Biology Society. Conference 1: 1311 – 4. doi:10.1109
So, I tried those frequencies. And after listening to the 1st one (High Beta to Gamma, Isochronic tones: 18HZ ramped up to 40HZ within 20 minutes) – I immediately stood up and started organizing! (Something that I kept forgetting to do!) Overall, I’ve found that isochronic tones & monaural beats are more immediately effective than binaural beats, though they are still good.
Altered states of consciousness: In as early as 1987 it was discovered that photic stimulation at specific frequencies produced an altered state of consciousness. An extremely small study with just 4 individuals involved photic stimulation at 6 Hz, 10 Hz, and 18 Hz. The results were reported to have altered their conscious awareness. This really isn’t that surprising to anyone that’s used brainwave entrainment therapy.
Some research suggests that the benefits from brainwave entrainment can last a lot longer, and still be seen for some time after you've stopped using it.  Study participants have still maintained improved test scores a few weeks after the stimulation had ceased.  Research on the long-term benefits has so far been minimal though, so how long the effects last is still up for debate.
Admitted, I haven’t listened to all the tracks yet, but while listening to the demo alone over the course of a month-and-a-half I, too, had a transcendental experience that was amazing! So I determined pretty quickly to save the money and buy your product, even though I really can’t afford it. Yes, over the last 3 years meditation has become that important to me.

This is a question I have noticed to concern many people, who are researching the issue. I have come across this question in forums, Yahoo Answers, in blogs, and all other sorts of  places. I can definitely empathize with someone who is looking to find a solution to a problem like anxiety, migraine, pain, etc., and needs reassurance and scientific proof that brainwave entrainment actually works!

Deep relaxation is another major benefit resulting from the brains cortical frequency following response while using brainwave entrainment. As the brain tends to mimic the rate of frequency it is exposed to, thus allowing it to enter into that brainwave state, this helps explain why this technology can produce benefits commonly found with meditation.
Brainwave entrainment is a colloquialism for such 'neural entrainment', which is a term used to denote the way in which the aggregate frequency of oscillations produced by the synchronous electrical activity in ensembles of cortical neurons can adjust to synchronize with the periodic vibration of an external stimuli, such as a sustained acoustic frequency perceived as pitch, a regularly repeating pattern of intermittent sounds, perceived as rhythm, or of a regularly rhythmically intermittent flashing light.