I went water only (full body) two months ago just to give it a try. I keep my hair really short so that wasn't as much of a factor as it is for a lot of people here. I also started with very dry skin and after a shower I had skin flakes/powder all over clothes etc if I turned a shirt inside out.
Day 1-4 I took daily water only showers with a washcloth to scrub. Immediately I stopped having such dry skin. Things felt a bit waxy but not gross.
Day 4 to 15 or so I was so greasy I nearly gave up (and had two years ago at the same point when trying this) but I pushed through. Once I dried off after a shower I didn't feel gross but in the shower I felt so slimy and greasy.
Day 15 to 30 dryness came back though not as much as before. Ironically I was wishing for some of the grease back at that point.
Day 30 things started to stabilize and my skin was a lot better than in the past with just occasional episodes of dry skin but nowhere near as bad as before.
Day 45 we got a water softener installed as we had very hard water. From that point on my skin has been even better.
In the last month or so I bought a natural bristled back brush and used it in place of wash cloths as I was getting some "backne" from not scrubbing enough there. I found out quickly that if I used it daily I had dry skin as I was scraping off too much of the natural oils. So now I use it every week and just use my hands to scrub head to toe (extra attention to face, pits, bits, butthole and feet) on the other days. With that regimen everything is great. Skin is better than it has ever been.
I was weirded out by the idea of not using soap on pits, bits, butthole and feet but figured I could always go back to soap on those parts if it wasn't working, but for sure I saw no need to use it on face, torso arms and legs etc as without it my skin in those areas was far more stable. Several times in the adjustment period I nearly caved but didn't. I am glad I pushed through as it has worked out for me.
I don't stink (confirmed by others). Nobody knew I was doing it until I said something. My own smells I noticed before after a long day or two like pits, crotch, feet etc are far less to non existent.
It's something that can't hurt to try. You can always abandon it or go back. Though I do recommend at least 2 months because it gets wonky in the middle and you can get frustrated.
It's also something that I wouldn't tell people about as many people seem to get really angry and argumentative about it. Sort of like people who change eating habits etc. Everyone wants to tell you why it's stupid, gross or wrong. They won't think you are gross or stinky until you tell them you don't use soap and suddenly they decide they can smell you.