My new X51 is right next to my Apple AirPort Express Base Station, less than 8 ft, and I'm getting only 3 bars out of 5 on it. I'm only showing one other WiFi signal, other than my own, w/it.
With my laptop, I get a full 5 out or 5 bars w/it, and it sees well over half a dozen other units in the neighborhood.
I don't know it is the metal shielding of the X51, the antennas, or a bad WiFi card. I ordered a couple of new cards on eBay, the Bigfoot Killer 1102, and an Intel 6250, and I'll see if either one works better than the Dell 1502. If there is no change, then it has to be either the case shielding or the antennas.
During the X51's development, this should of been seen.