Maybe yours is faulty, but one thing I did take notice of is the mic cable can cause problems with some gear; particularly, if using a 1/4" extension that blends the mic and right channel pins together.
Keep in mind that V-Moda has a 60 day satisfaction guarantee. That gives people plenty of time to wrestle with the idea of returning or keeping the headphones.
It's a very good headphone. I'd say it's a very FUN headphone. It's extremely portable, has a lot of nifty features, and has some cool warranties covering it... on the website it says something along the lines of, "If you do manage to run over your V-MODA M-100s with a tank, send them back to us and we'll put 50% of the value towards a new pair."
That's pretty cool. These are not audiophile headphones by anymeans, but I own the TH-900s and I absolutely love the M-100s. They keep me company when I can't get my Fostex fix.