That’s a smart choice, I hope you end up liking it!
I would have reviewed one of these myself by now, but I felt like it would be a little redundant to my DT770 and Custom One Pro reviews, and since I buy everything I review myself, I couldn’t quite justify the price of it haha.
The MMX300 is a bit of a frankenstein headphone, but you’re getting a lot of the hits of the Beyerdynamic lineup. It combines the DT770 drivers and pads with the headband and removable cable from the Custom One Pro, along with a really nice integrated mic.
Let us know what you end up thinking of it!