M1, 4 converts to methyl boldenone which is dbol. I have used both m1,4 and dbol at 50mg ED. The comparision I saw was pretty much 40mg/dbol = 50mg m1,4. Not so much of a diff, obviously. One GOOD thing I liked with the M1,4 as the fact that dbol makes me shed hairs LIKE CRAZY!!! No joke, usually will grow back though. But the m1,4 didn't make me shed a bit, go figure. My advice would be to do either, can't go wrong either way IMO.
***also, some guys were using upwards of 150mg/day of the M1,4. WHY?? No idea, but to me that is way overkill, i was 240 or so when I used it from DS back in the day and got great gains dosing it at 50mg.