how good is it? MHO ...not good.
its strong. its a likely progestin. its suppressive.
IMHO it unsafe, untested and with numerous unknown long and short term side effects. Liver damage and cancers being of chief concern- these are found with other orals (even without elevated numbers)- many of the discarded orals (ones that did not make it to market- these occurances were unnacceptably high)- this oral was not even discarded- so there is no safety or testing data.