I followed the Surface Laptop announcement pretty closely, and to be honest I don't see how different this laptop is from your standard (and already excellent) XPS13.
The only two differentiating points I see are the 3:2 Surface display and the Alcantara fabric (which I don't see why so many people are hating).
Even then, there are a couple of devices here and there with 3:2 Surface displays also.
The ram and SSD are intergrated (first time anyone has done that). Which leads to lower power consumption (and thusly also longer battery life), as well as lowering bus bottlenecks.
The butterfly-type keys might be a selling point to some, as might the seemless form factor, the thin touch screen, the weight, and the lack of bordering on the screen, one finger screen opening. Some even might just like the attractive form.
They did claim that going away on holiday, if you returned the battery would be exactly the same as what it was. IDK how that works, but maybe they have slightly different battery tech (because standard lithium loses charge unused)
Specwise, if your a spec person, there are better tablets than either the xps 13, or the surface laptop. Razers gaming offerings for example. It kind of depends on what one is after. xps 13 and surface laptop, certainly have numerical similarities.
I think because of things like the intergrated ram/ssd, it would probably make sense for someone to do some strong benchmarking with the device, to see what the user experience is like, because by the sound of MSFTs claims (like extra long battery life), some of the benefits of this device might not be obvious from specs people usually pay mind to.