Very recent purchase, large crystal chunks in a somewhat translucent grey. This was sold as Ephylone, BK-EBDP, or N-Ethyl-PENTYLONE.
I think I initially dosed around 80-100mg and then another 80mg 2 hours later, insufflated.
Come-up is not too heavy and the experience for about T+0:45-2:00 is fun. Very chatty, good socializing but a bit dominating in conversation, cutting people off and whatnot, but this is to be expected with most stims, at least for me.
I would compare the initial effects and plateau to the 4-FA buzz, mild but noticeable serotonergic activity, especially in terms of the emotional sharing, but not full-blown rolling by any means.
Definitely has that quality of "emotional vomiting" that I often find with empathogens, where I start talking about weird relationship issues, fluid sexuality, does anyone want to dance, hey can you do my makeup, hey have you ever had a threesome JUST CURIOUS, etc. Idiot.
Redose made me especially tweaky, and I was definitely chasing the dragon, in a way that is predictable with serotonergic cathinones. Having gone through a few grams of mephedrone (4-MMC) in the past, I'm familiar with this feeling but have never had any problem with one or two redoses.
After the initial rush from re-dose, the whole thing went into pretty bad territory. Side effects became more and more pronounced as time went on -- elevated heart rate, very bad dry mouth/dehydrated feeling, general tweaky confusion. Comedown was god awful, I felt like I had EXTREMELY high body temperature even with the AC on full blast, and wish I'd been lucid enough to take my temperature. Sweating like crazy just sitting on the couch. Very nasty residual stimulation. Took high dose melatonin, valerian and benadryl in order to sleep at about T+8:00. Managed to eventually get to sleep for maybe 6 hours, was absolutely destroyed for the rest of the day. Weird residual stimulation lasted for almost 3 days - extreme sensitivity to caffeine, anxiety, heavy teeth clenching. Plus the serotonin crash. I have a pretty good pre and post stim/roll supplement and diet regimen, and none of that was very effective in this case.
Dose was taken thursday night and it's monday afternoon and I'm feeling okay. Recovery took the whole weekend. Would not say the same for light meph or 4-FA use. I have the impression that the serotonin depletion was not super heavy, but that residual stimulation was pretty terrifying. This was not a hardcore binge by any means.
I want to note that the trip reports I read for this substance list wildly different dosages, some as low as 30-40mg for a fully recreational experience. My tests at those doses yielded effects about on par with 15mg adderall, and did not align with the descriptions from those reports.
tl;dr -- the reward from this chem is definitely not worth the side effects. Stick to the substituted amphetamines for light rolls!