Chassis Construction and Durability of Precision and ThinkPads

I'm interested in comparing chassis construction and durability/reliability of Dell's Precision line and Lenovo's ThinkPads. I could not find much information on either site regarding chassis specs and material. My understanding was that both Lenovo and Dell used Magnesium Alloy in the exterior of the case. However, I read recently read on Dell's website that they are now using anodized aluminum. Wouldn't magnesium be lighter and stronger? Is this a move backwards? Any info on what either company uses and which is better would be greatly appreciated.

Thanks.

 

In all of the current E-Series, you've got a mix of plastic and metal; the base is magnesium alloy, the palmrest is plastic, the display bezel is plastic, and the lid is magnesium alloy with an aluminum finish. I'm not totally sure about the M6400/M6500 which is built differently, but I'm pretty sure it's mostly magnesium alloy with an aluminum finish as well.

ThinkPads are built similarly, with maybe a bit more allow and a bit less plastic. They also finish pretty much all of the alloy and plastic with their rubbery ThinkPad finish.