Many have used it.... the majority loved it.
Some complained of an initial "break-in" period.... where sleep was difficult. This wasn't the case with me. Deep Sleep, immediately. All in all, REM is quality stuff.
I will say however, that the combo of cAMPhibolic, PowerFULL, and Cissus I pop pre-bed now seems to exert a good sleep effect as well.
REM: Worth the cost. Use less than recommended, still good effects, stretch that bottle out.