It's probably no surprise to you that if only one person on Steemit has tried it, it will be me :-) I was attuned to it first around 99/2000. Then to level 2 in 2001. It was the first modality that I trained in myself. I use it sometimes with clients, mostly when it comes up in the context of a kinesiology balance. But there are a lot of Reiki people in Wellington, and my other skills are more rare. So if someone wants just Reiki on an ongoing basis, there are other options.
When @sift666 was first diagnosed with the brain tumour, I was doing nightly treatments. I don't think it fixed it, but it relaxed him, so he could sleep.
In our training we were taught that the energy came through us, not from us. But like you, my experience is that energy received from different people feels different. I'm not sure if that means that our ability to be a clear channel differs. Or whether some people have their own innate healing ability which is added to the Reiki energy. A friend who trained when I did already had a sensitivity to energy in her hands. Reiki from (through) me is very relaxing, but from her it feels more powerful (so I've heard).