Usage Notes, Battery Life, and Conclusion
Battery life was about average with the UX390UA, but with a 15W processor there is nothing to really complain about here. We use a 180 lux screen brightness (71% on this screen) for this test, and if you use a lower brightness setting (I am generally at 120 lux) then it should last much longer than 6.22 hours. The lower TDP part in the XPS 13 2-in-1 fared much better, though the ThinkPad X1 is quite impressive with its own 15W Kaby Lake CPU.
The Zenbook 3 UX390UA is a stylish-looking (if you care for the blue/gold color scheme) and in use was quite responsive thanks to fast solid state storage and that Core i7 CPU, but it was not perfect. I must mention the fan noise again, as any time the CPU did any sustained work during my evaluation period the fan would spin up audibly, and remain there for some time. The combination of a thin unibody chassis and a 15W Kaby Lake Core i7 CPU does work with a conventional active cooling system, but you will hear the fan quite a bit.
The machine itself is typical of the razor-thin aluminum designs that follow the MacBook Air (sorry Apple haters, this is the design template and worth mentioning). My own opinion on this design – be it Apple or ASUS or whomever – is that it is rather trite at this point. It's all a matter of preference, but I personally like designs that offer something more unique. But that was not my primary, everyday complaint – though it is hardly unique to ASUS with this ZenBook: it has only one I/O port. It is a trend that I strongly dislike, and I make no excuses for it on behalf of Apple or the companies who followed Apple in eliminating most of a laptop’s I/O. Yes, a bunch of dongles can be daisy-chained together to offer similar functionality to a useful design, but this is – at best – inconvenient. Still, credit ASUS for providing a practical dongle in the box, where Apple simply smiles and takes more of your money with zero adapters included with any portable machine.
In closing, I found the ZenBook 3 UX390UA to be a capable laptop with an excellent display, solid trackpad, and very good overall performance (with some very noticable fan noise at times). Battery life was not exceptional, but certainly not bad considering the 15W Core i7 processor (which I discussed at length in the review). The color scheme of dark blue and gold was not one I would personally choose, but the laptop did offer a high level of fit-and-finish that made it attractive regardless. A price tag of ~$1450 at current pricing (there is already a replacement to this machine with the new UX490UA) isn't bad considering the spacious 512GB PCIe SSD and Core i7 CPU option, and if you pick one up you would immediately appreciate the solid – though very light – feel of this laptop. If you like the style and need these high-end specs, it's a good option.