What the heck is the Surface 3 being compared to the ZenBook? They're 2 totally different machines. The ZenBook doesn't even have a touchscreen. It doesn't have a pen option.
The situation is so simple. If all you want is a laptop and best performance, you're not going to pick a Surface 3. But if you want a machine that's ultra flexible in a very thin body with a fantastic touchscreen with a 3:2 aspect ratio, a pen option, a detachable keyboard, multiple keyboard options, etc., then the Surface 3 is a very viable option. People have different metrics. If your only metric is the cost and the performance, then look elsewhere.
There's so few machines in the Surface 3 category really (laptop/tablet with a pen option). There's Toshiba's Encore machine. There's Lenovo's ThinkPad 10. Dell's Venue 11 has an awful pen option.
I'll take the Dell XPS 13 as an example. Beautiful laptop in so many ways. If I wanted a regular laptop, I would get that one. But I don't want a laptop. I can't rip the keyboard off the Dell. I can't use a pen on the Dell. By every measure of a laptop, the Dell beats them all. Have you ever used a laptop while standing up? It's really annoying.
People like Geodude just don't get it. A tablet will never be able to be like a laptop. And a laptop will never be able to be a tablet. A Surface machine gives me options. I can be in any situation I am in the mood for. When I feel like ripping off the keyboard, I can. You will never ever be able to rip the keyboard off the Dell. When I want integrate into my PC network and have a complete workflow with big software like Adobe stuff, I can with a Surface. An iPad Air 2 will never run real Photoshop or InDesign. Sure, you can juggle two machines. But people would rather have 1 machine. That's why people have a smartphone with a GPS app versus a dedicated GPS device and smartphone. While a dedicated GPS device has many features that no GPS smartphone app has, people are okay with just owning the smartphone.
The ultramobile hybrids (the Asus and Lenovo machines, for example) and the ultramobile tablets (Surface machines are classified these by Gartner) are the only growing segments of the portable PC market. People are adapting and buying differently because there are now more options.