Been rocking the MX2's for a while now. Still solid and sound great. May upgrade to the MX 5 when the prices start to fall.Naming does not matter too much. I am disappointed Sony continues to cheap out in materials - my Mark 2s are so solid compared to my Mark 4s. All else being equal, the power button is actually a fairly big deal and if I were looking for a new pair right now, the Mark 5s would edge out the APMs just on that alone.
ETA: was not a fan of the digital crown control on the APMs for the short time I tried them, either. YMMV.