I actually enjoyed Sins Past (I would had preferred that it had been Harry's and not Osborn's children).
OMD was for me bad in so many ways. It was to long ( Second and third felt like a complete waste of time), it had horrible plot points (No on can save May from a freaking bullet wound) and the reason for Mephisto wanting the marriage was stupid. and OMIT manage to make the OMD worse.
So yeah OMD for me, and I do think that it is the most hated of those two even though is probably a close one .