I'm not sure how many of you follow other Alienware forums, but I happened upon this one over at notebookreview.com and was shocked to see the large number of disgruntled m15x owners. Most of the complaints seem to stem around heat dissipation issues and downclocking of the 8800GTX while gaming.
I'm currently in phase 4, but after reading all those posts, it's frankly gotten me a little worried...