the m50, and sure 440 are in my roatation of what I call my semi portable group. I don't wear these when walking around, but through them in my messenger bag for use in the coffee shop, library etc. I have had mine for several years and the only thing I have ever done is to replace the ear pads. I do put them in a protective bag before I throw them in with books etc. I use bags sold on amazon under "good cans" They are slightly padded. well worth the $20 or so.
The sound signitures are quit different. I use them with my Ipod a line out and an amp. Fiio E11 has worked well for me. the amp and line out provides a great improvement with the ipod. Last note, I think the 440s are greatly under rated. not saying better, just different and also very good for the price. I could be satisfied with either.