I've done this drug numerous times now, mostly smoked but a few oral trips and once insufflated. I also agree entirely with Jaw Clenching about its effects, although i'd say it's less like MDMA than people are letting on; the energy is way more tryptamine-like. I find that 5meomipt makes me incredibly animalistic in the sense that I will jump and swing around and climb up trees and overall just be full of energy with a sense that I can't 'stop'. As far as the second part of the trip it is incredibly psychedelic, some of the strongest visuals i've ever had came off a 15mg oral trip - though it seemed to be lacking more than most trypts i've tried in the mental department.
Smoked i've done from 2-15mg at a single time and i've even done up to 40mg in the span of 2 hours or so. I find smoking 5meomipt to be easier to handle than orally (considerably less intense) and the doses are larger, and as well it doesn't seem to have the same 'two-phase' trip that it has orally - instead it has a 30 min. psychedelic peak followed by 3-4 hours of stimulation/body high.
Orally, this is definitely one of the more interesting psychedelics. The two-phase trip is incredible if you're careful with dosing (easy to go in way over your head).
As for combinations, i've taken 10mg oral with 1/2 pill of clean MDMA. This yielded vertigo, nausea, and way more energy than I wanted at the time. All in all, not the best combination.
However, i've found a gem of a combination that a few of my friends at the moment view as the holy grail of psychedelic experiences. Smoking 5meomipt on the peak of a good LSD trip. I have only done this once personally on 2 hits of LSD which ended up being a really weak trip due to some tolerance I had, but after smoking ~5mg of 5meomipt I had a really strong body high and then all of the sudden my entire frame of vision was covered in fractals and I closed my eyes and thought up some of the craziest shit of my life, lol.
My friends who've smoked 5mg on 2 hits and 3 hits a few times all say that it boosts the level of the trip considerably and the visual and mental effects are second to none. No problems have been reported yet with this combo either, though I imagine it could be incredibly intense (and bad) if someone were to do this in a bad setting.