I have 2 M70X, great transparent and accurate sound, easy to drive, not expensive for the sound. But they each broke after a year of regular moderate use. Actually after my first one broke after 1 year, i bought the second one hoping with a more careful use it will not break so easily.
I called the service centre in Singapore, the repair cost is half of the selling price. As they do not sell the smal plastic join that broke, but I have to replace the whole bridge between the 2 speakers.
So if you have a M70X, better add some reinforce resin. But expect the life to be 2 years max.
If Massdrop could source the small plastic join piece I will be the first to buy. After all it's a big waste for a pair of perfectly sounding headphones.