I have done 30 up to 100mg per day, of course it was for a very short time. It greatly benefited my strength and power. But I don't think that's the dose to use, I believe 30-60mg/day, depending on how long you want to use it.
Overall I'd 30mg/day, doesn't interfere much with daily life and tasks. Provides some good boost and if taken for a bit longer that nice and quite pleasing cosmetic effect. Only negative like mentioned in this thread multiple times is lipids.
Higher dosages of 50+ of course add more performance gains, but as others have mentioned some get really bad pumps or even cramps. Possibly more aggression, less tolerance for random bs, acne, sleep issues from mental overdrive as body can feel overstimulated. Also BP issues, shortness of breath, increased heart rate, dehydration and etc. are possible.