I'm glad you felt positive about your first Goenka(vi)passana retreat!
I was angry at meditation for about two years after my first retreat. Arguably, that was a deepening of my practice of mindfulness as I had been angry for about 15 years already and I hadn't ever wanted to noticed it. That "noticing what is obvious" part of meditation always surprises me - is THAT what I've been feeling????
I've often thought about taking a second Goenka'passana retreat . . . maybe not quite yet, though.

As for the Reiki stuff, I admit I'm skeptical that the experiences quoted couldn't (or don't) happen to most meditators at some point. Burning, buzzing, exploding energy? Check - felt that; felt all kinds of things. I think we will interpret our far-out sensations based on our own preferred esoteric anatomy paradigm, but I assume that most everyone will feel them when they meditate.
I believe that Goenka's school wants people to choose either Goenka'passana or (insert practice here) no matter what it is, Reiki or not. He's a little absolutist in that way . . . he also refuses to participate in ecuminical/intratradition Buddhist dialogues. He wants it "pure" as he was taught/teaches it and I truly believe he offers that choice for the good of the student, as he sees it.

I was able to attend a 10 day retreat a couple of years ago, and it was a powerful experience. It's true these Vipassana retreats are hella-intense, and very strict- certainly not for everyone. It seems to me that Goenka's intention in developing the retreat style is to offer a powerful and direct experience of vipassana. It's a no b.s approach- if you're gonna do it, Do It! I've even heard that the Dalai Lama sent some of his highly trained monks to a retreat and was so impressed by the result he helped open a centre in Dharmsala. (thus have I heard, anyway).
My own experience within the retreat was pretty intense and uncomfortable. I was jumping out of my usual tradition (Karma Kagyu/ Nyingma) and was pretty freaked out at first by the style and approach. Not that it was "so weird", but it was something very different from how I had been taught and within that claustrophobic environment I got quite scared. I'm happy that I stuck it out, though. I walked away with an experience of meditation that eight or ten years in my own tradition had never given me. I'd never abandon my own Mahayana ways for the Goenka sangha, but I would love to have another experience in Merrit someday soon.
As it turns out, while I thought I was going against my own tradition when I went to Merrit, I found out later that one of my teachers, Ponlop Rinpoche, likes the Goenka style very much and accepts a ten day as part of his practice curriculum. In other words, a lot of my worries were completely unfounded. (surprise surprise).
Something that really impressed me about Goenka's gig is that he offers his retreats FOR FREE. As far as I have been told, his entire international organization has been born and cultivated on a donation basis alone. Furthermore, he only accepts donations from people who have done a course. You are not allowed to offer money until after your ten day experience! It is hugely inspiring for me to think that someone has managed to undermine the entire business model of organization, and is brave enough to trust the generosity of human beings to keep his work going.
The website, for anyone interested, is www.dhamma.org. There is a retreat centre in Merrit, B.C., and many more across North America and the world.
Congrats again A. It is a brave thing for any of us to be willing to sit down with our own minds, and also a beneficial thing. May all beings get good juices from our practice, and all the trimmings.
Z