I own both the Grado Reference (the Reference) and the Dyna 10x4 MkII. I really like them both, but the one that stays in is the Grado. For three times the price it ought to. However, the comparison is really close. Both are very smooth throughout, but the Grado is just a bit more 'there'. Not having heard the Platinum, I would have to venture a guess about that comparison, but my guess is that any compromise on the Grado side would tip the scale toward the Dyna.
