^For anyone whose looking: search for psood0nym (that's psood>zero<nym) in this thread to narrow the result. Most of my posts about experiences have been from using IM.
I have tried vaporized freebase aMT to test it out fairly recently. I only used 4mg, though, so it probably wasn't enough. It was also while using a small dose of Adderall (incredible combo), so it's hard to give my judgment. It mostly just seemed like extra stimulation at that level. I was surprised how much noxious vapor was produced from such a small amount, and so so long as there's no potency increase or a substantial qualitative difference I'll probably just stick to IM.
I tried IV to see if there was a further trend towards increase euphoria relative to psychedelia like there is, in my experience at least, from oral to IM. The shortened duration and qualitative difference is the whole argument for IM. But yeah, aMT is like LSD that way. There's no advantage over IM (though I doubt IM LSD is qualitatively different than oral because it isn't a powerful releaser of dopamine and serotonin the way aMT is--which, BTW, because of its faster onset and presumed resultant greater DA/SERT release, IM aMT may be more neurotoxic than oral aMT (the same might be true for vaporized)). Also, my quoted onset time for IM aMT is probably a little sooner than most because I'm familiar enough with to be really sensitive to first alerts and because my body seems to process it faster than it used to. Dondante has an IM aMT/DPT (one of my favorite combos, just don't use 100mg DPT like him!) report in Trip Reports that might supply another data point on the subject.
Freebase aMT can be easily converted for injection using plain old white vinegar (which is very sterile). I've converted synthed DMT freebase to DMT acetate for injection this way by putting the DMT in a small glass vial then adding 5% vinegar (dripped from a syringe) while heating and sloshing it around on a hot plate (frying pan works fine, too) until it was dissolved (DMT didn't take long). Then I diluted it with some preservative free sterile saline contact lens cleaning solution (sodium bicarbonate should also work to neutralize), ran it through a filter and IMd. It stings a little (goes away quickly), but that's because I just don't bother to neutralize fully.