I know and have known a number of Reiki masters..and folks at various levels of training and atonement (at-one-ment).
Reiki has two main forms as I know it, an Indian version and a Japanese one. It is quite systematic, dogmatic, steeped in tradition.
My belief, like religions, all the hands on/off healing techniques come from the same source and utilize the same source energy.
So whether it it Tui na, Jo rhe, Reiki, Ki gong, or even healing touch (the US nurses sanctified method of energy work) it is utilizing love and G!d as the energy and a practioner as the conduit.
As for efficacy, I'm a participant and have seen some incredible stuff. But I'd still go to an allopathic MD to get a broken bone set...I may go to energy work or accupuncture afterword for pain management and additional healing...