Both are very fine choices. I find myself using more of the Miprocin for some reasons. 8)
I prefer Miprocin in lower dosages, like 10-20mg, whereas I like Metocin when its 20mg or higher.
Metacetin (4-AcO-MET), on the other hand, I find to be the most versatile and probably the best "mixer" psychedelic - mixed it with dozens of different psychoactives to very satisfactory results.
Miprocin is very relaxing at low dosages, with soft fuzzy lights, light entactogenesis and almost a drunk disinhibition. Going up 20mg and higher it becomes quite powerful with neon visuals, pronounced stimulation, deep and somewhat alien psychedelia. I successfully redosed on it couple of times - even a 5mg booster dissolved in acidic drink bring you up and add to the trip 5-6 hours after the fist dosage.
Sex is possible and actually is very fun on Miprocin, I feel that it brings out a male energy from within me, I suspect high adrenergic activity of it.
Succesfully mixed it with MDA, 6-APB, ETH-LAD, 5-MeO-MiPT. It was not so good with 2C-B-Fly but more trials are needed with it I think.
Metocin is kinda weird in low doses and I feel underdosed. Once it kicks in though, its beautiful - very colorful and fully 3-D CEVs and OEVs. For me it takes about 25-35mg to fully enjoy it's qualities. About 20-25mg in combination with MDA or 6-APDB - that combo is one of my favorites!
Sex is probably possible on Metocin but not really desirable, definitely not like with Miprocin.
Have not tried redosing with it as it feels that theres no need for it, again, not like with Miprocin.
I feel the Metocin character is more defined than Metacetin (so less desire to mix with other stuff) and I've only mixed it with MDA and 6-APDB to a great success. I feel that it would be nice to combine 4-HO-MET with some x-scalines too.
Also Metocin has a considerably shorter duration than Miprocin - about 6 hours tops for Metocin and up to 8-10 hours with Miprocin IME.