Great review Dale!
I recently bought the AKG K550 based on a few reviews and a brief test with my phone but when I got it home I was really disappointed. I need to take them back to the shop as a sanity test to see if they think they are broken because there is so little bass and such harsh highs if you turn the volume up at all that they sound very veiled and I can't enjoy them at all no matter how much time I spend with them. If they turn out to be functioning properly I will post my review of them on my blog.
I recently borrowed the M50 from a friend at work for an afternoon and was really blown away by the feeling of the sound. I was even more impressed by them than with the VModa's and that's really saying something because I really love the M80 a lot! But i need something more comfy for the office and the M50 is perfect for this! I am going to be trying to get hold of a pair as soon as I can get rid of the K550, if's it's not broken that is.