Eh. Everyone's ears are different, and that's honestly a great price for them (I'd take a pair for $60 and happily listen to them). I think the ProDJ100 is my pick for 'budget' cans, but you didn't like it. That's fine.
I also don't like Grados. :D But they're definitely more love and hate than M50s are.
ProDJ00 is one of the worst headphones I have ever had the displeasure of hearing. I would take Senn HD280 or Audio Technica T400/AD500 or Superlux, or any Samson oem product over it any day of the week. In fact I did, until I got my hands on a second-hand M50.
I don't think I'm on Head-Fi anymore.
I got my M50 for $60, $21 less than I spent on my Grados.
If Grados are universally herald as the entry in to audiophillia, and M50 is the obvious step up, why are people saying they aren't good? Nobody is saying they are the end-all. In fact, I regularly demo flagship systems, and they are very obviously only a marginal upgrade to what I currently own.