Yosef:
Excellent question. There has been much discussion and comments on this forum concerning Holosync; you might want to look up these past posts.
In and of itself Holosync is an excellent program: it aims to enhance the meditative state by inducing certain brain wave patterns which are often associated with deeper meditative states. Therefore, Holosync music is pretty much coded music; loosely speaking, somewhat akin to hypnotic meditation (sometimes associated with medical hypnosis). However, this latter point is what might become the "detriment in using Holsync music instead" as you specifically asked.
Before going any further, please understand that I have nothing against the use of Holosync; infact, quiet the opposite; they are doing an excellent job and deserve their due praise and accolades.
However, Spring Forest QiGong (SFQ) is a complete system in and of itself. It works just FINE in and of itself. There is a lot going on in the practice of SFQ: the visualizations, the breathing, the wearing of a smile, the moving of the Qi in and out, the calling upon the Master's energy, and the entering of the silence (to name some of what is happening in the active and passive [meditation] exercies). As your practice deepens, and this all becomes natural to you, and somewhat second nature, you will become a part of and experience the AT-ONE-MENT of the SFQ meditation: the process, experience, and results are synergistic and comprehensive.
Why then would you want to superimpose a scientifically preprogrammed meditative energy system upon something that is already PERFECT? Would you seek to paint the wings of a nightingale, because you have found a beautiful paint? No! I don't think you would.
The music supplied with the SFQ material is just beautiful music. You may use any other music you would like to substitute. But, Holosync music tends to be in a unique energy class.
Later, when you have sufficiently mastered the basics and experienced the distinct and profound effects of SFQ meditation (and do not forget the Active Exercises); then, by all means, experiment to your heart's joy - and then some: because you too are a master awaiting unfoldment; like the butterfly is the caterpillar, and you are me, and all is all - the silence....
Much Love....