aMT at around 25mg orally last Saturday gave me 12-14 hours of strong euphoria (on a par with 150mg of MDMA), and was absolutely beautiful. I did manage to drink a lot, which felt very messy, coming off the aMT though. By comparison, MDMA gives me typically 3-5 hours euphoria, plus a couple of hours residual stimulation. aMT was wonderful as it ramps down slowly, appears to enhance music nicely as well.
I'd say aMT is on a par, euphoria wise, as MDMA is, but the trippy aspects make it very interesting. It doesn't seem to have much of a comedown either, more an afterglow which lasts a few days.
I know nothing about Opiates though, as I have no real interest in them (prefer stimulants/psychedelics, plus the addiction aspects of Opiates scare me off).