It's not an easy question to answer.
Specification wise comparisons tend to be hard to do as there are a number of features that are never the same between vendors, ASUS and Lenovo (thinkpads, formerly IBM) tend to offer similar specced machines in regards to processor, GPU and screen size, though Lenovo's comprable GPUs tend to be of the mobile workstation class. Aesthetically, there aren't really any machines that match it to my knowledge. Of course if the buyer wants OSX (legally and supported), mobility and features that macbooks don't have then there is no competition.