I have been a very infrequent practitioner of meditation since 2009. I am now a very different person and there is no way for me to measure how or what has changed in me. I am way more focused, happier and might I conservatively add the word "successful" in my married life as well as financially.
As most of us have a very scientific attitude towards life, we all can atleast experiment with it. If it works for us, then good. If it doesn't, just move ahead. I have no instrument which can measure my experience but I don't need to google it to know if it has worked for me or not.
Again all I am saying is that please dont have the attitude "Whatever is not written in the books we studied or if there is something we can not explain with our logic, then it must be mumbo jumbo" is the ultimate ignorance. I am not saying that we stop doubting and accept Reiki at face value. I am just saying to keep a scientific attitude, experiment with it and see if it works