I first did kratom back in 2003 I think it was, there were a couple of report on Erowid and I came across a head shop that was selling 10 gram bags, so I bought one. At the time you could only get crushed leaf, not powder. The only method of consumption I read about was brewing tea the traditional way, which involves gently simmering your dose in water for 15-20 minutes, and then straining out the leaves and make a second tea the same way, then combine and cool. As it cools it goes from a brown/red color to the appearance and consistency of coffee with cream in it. Maybe a bit lighter. It tastes horrible, but my god... I had done vicodins a few times, didn't really think it was anything special, but kratom was amazing to me. I really find the experience different with downing finely powdered leaf. You hit the dizziness/weird place much quicker which doesn't allow the best parts to fully develop.
That first time at 10g, I was in my friend's car and drank it. We were just driving and smoking, I think it was Thanksgiving or something and we were visiting our families from college. In 20 minutes I felt an amazing rush, it was kind of like really good coke, I felt like I wanted to talk about everything and move around a lot, I was so excited. Then it hit fully and I had to have my friend pull over so I could throw up. But it was the second best I'd ever felt from anything at that time, and honestly to this day. I felt better in my early MDMA rolls, and from some other things, too, in the intervening years, but it was really something. Pretty quickly I found where to get it and started buying pounds. I kept doing it, more and more, for 6 years, and at some point it shifted to the finely powdered form and I swear it's just not the same. But it could also be that my receptors were no longer virgins. I ended up eventually upgrading to harder opiates and eventually quit opiates altogether.
I can safely say that my favorite opioid highs on anything have been kratom (I have never IVd anything so keep that in mind, I always figured crossing that line would end with me dead), in those early years. But these days, recently I had a bit of a relapse, which started with kratom. These days it makes me feel pretty nice for a short bit and then BAM, instant withdrawal mode. It's weird.
In the US, we had an incoming ban, amazingly, be stopped by basically a petition, there was so much pushback that it didn't happen.
I have withdrawn from heroin, poppy tea, and (very) heavy kratom usage (like 50g a day). Heroin was the worst overall in terms of hos sick and empty I felt, but kratom had the WORST RLS. I fucking hate RLS, I used to just get it when I was a kid constantly all the time, before it was a recognized medical condition, my brother and mom and I all get it, and our family doctor basically told us we were crazy and just don't move our legs. Anyway, the worst part of opiate w/d, to me, is the RLS, because it drives me fucking crazy, and I can't sleep at all no matter what. I don't know what the worst part for you is, but yeah, the RLS was awful, but again, I was doing a huge amount, and for a long time. I didn't feel sick like with other opiates though, I didn't get nauseous or anything, but there was a ton of anxiety. Pretty similar, but different. One nice thing is the withdrawal is shorter than most other opioids.