Hey, I just got my new Dell XPS 15 L521X with almost the highest end config with 16GB 128SSD+1TB etc. here in Feb 2013. I am having the same issues described here with WiFi (35Mbps internet but can barely get 5Mbps down even sitting next to the router - 2.4 or 5ghz). I guess that would mean they are not shipping the new laptops with this 'display hinge kit' / 'new display/antenna' config. That is pretty disappointing after dropping about $2k on a laptop. I'd suggest Dell do a proactive replace plan if they ever want to keep customers buying their high end stuff.
Has anyone else had this 'fix'? Did you have to go through a bunch of hoops with support or it seems this should be known and they just come to your place and fix or what? I will be calling but wondered what other experiences there have been out there getting this fixed. Fortunately I bought this through Costco so I can return without a hassle which I may do but what a shame I do love the design and attention to detail on the build but of course I need reliable WiFi.
Thanks to anyone that can share their experience. I'd love it if there were a software fix but totally makes sense with the aluminum body that this missed some real world engineering Quality Control.