Tried 55mg of this substance after 1mg allergy test. Which is a bit stupid, because it's FAR more likely to be the wrong drug than for you to have an allergic reaction to it, so I should have started low and worked my way up. But with a suggested 2 hour onset, I got impatient and stupid. It was worth it. But fortunately, 5-IT has profound and magical effects like MDMA, and so it's unlikely I will ever make that mistake again with any drug.
Quick summary of my experience before I write up the trip report sometime (I took ENDLESS notes while on this substance, they need editing because every single paragraph had an aside...) because I noticed some fun things no one else appears to have mentioned:
I noticed first effects after maybe 30 minutes. They just weren't STRONG, but unmistakable to anyone with a bit of stimulant drug experience. 55 minutes in, I wrote: This feels like the day after a dose of 4-fa. I cleaned my house, i feel awake and alert and motivated, but there's a residual druggy feeling going on. I'm still hungry, and have made a sandwich, but I think that's starting to diminish. Five minutes later I made the point in my notes that I was surprised people were allegedly redosing at this point due to lack of effects, because although still light, were unmistakably gradually building up, in delicious but subtle waves.
An hour and a half into the experience I note my amazement that it just keeps building up. Nothing overpowering, nothing dramatic, just better, and better... By this time I'm sidetracked on all my notes, this drugs is empathogenic like nothing other than MDMA in my experience, it makes methylone seem halfhearted and insincere in comparison.
2 hours in, still increasing in light happy waves of seratoniny goodness. If i'd had the chance, I'd have headed to a club at this point, the musical appreciation is increasing. At no point have I had the MDMA rush whereby I'm forced to dance due to the intensity (as an aside, I've advised everyone who's ever done their first MDMA to dance when it first becomes overwhelming, as wow, that certainly fixes everything)
3 and a half hours in I've noted 'every time I think I've finished coming up, it keeps coming more and more'
5 hours in, I note it feels like it's leveled off. At no point do I feel underdosed or underwhelmed.
6 hours in, the following was noted: At the moment this feels exactly like 5 or 6 apb if they did not have any sort of trippyness. A couple of joints exacerbated the whole thing, but whereas on one of the apbs a bit of weed would make it much trippier, this just got you quite stoned too. It's still very nice, and the time does not feel dilated at all, so you're enjoying it for a LOOOONG time.
Went shopping at 7 hours in, the walk to the shops listening to house music reminded me how utterly wonderful this would have been in a club/festival situation. There's no URGE to dance, but when the music is on, holy shit you want to get crazy.
At this point, I drank a couple of pints of milk, and noted (because the empathogenic effects are TOTALLY still in effect after all this time) that I should report on bluelight the utility of milk on stimulants, it being easy to drink and calorific enough that it will not matter if you miss a few meals.
Another straight paste from my notes: So, this is continuing to be nicer and nicer as time goes on. This is seven and a half hours after I took it, approximately 6 and a half since first effects, and it has not peaked yet. It's the drugs speaking, so this is totally biased, but this stuff is fantastic.
9 hours after initial dose, 7.5 ish hours after first effects noticed, I finally feel it's levelled off.
Sometime later, I feel very tired. I don't think the stimulants are keeping me awake at this point, but I still stay up ridiculously late. Given I fell asleep immediately after trying I can't say when the drug effects wore off, but it was certainly subtle, (and probably masked by the drink and weed I did in the last few hours).
In summary, this stuff is fantastic. It lasts a ridiculously long amount of time, you can actually enjoy it for the full period of time because there does not appear to be any sort of time dilation, the empathy is like nothing other than MDMA in my opinion, and I experienced no comedown effects whatsoever. I'd probably try a bit of a higher dose next time, but in no way would I have suggested that 55mg was a disappointing dosage.
Unlike virtually all stimulants I have ever tried, there appears to be no problem at all reaching orgasm. However, this was not attempted till the comedown, so peak effects might differ

Also, note that I dosed at 1pm, and it still kept me up virtually all night. No overheating was noticed, although I did not do any physical activities while under the influence.
Having reflected on what I just wrote, I feel an explaination is in order. Methylone does indeed make you superbly empathetic, however I believe the difference between it and MDMA is the PUSH that forces you to be so. MDMA might lead you to saying things you would regret the next day, and I think it unlikely that Methylone would. 5-IT is far more like MDMA in this effect than methylone, which you may or may not prefer, but I absolutely do.