Honestly, almost an impertinence

The good:
1.) The 4K screen is excellent (see below for limitations).
2.) The processing of Ultrabooks is adequate for the price. The folding mechanism works well.
3.) should be mentioned also the good sound system is very positive.

The bad:
1.) The processor (Core M) is extremely underpowered. In conjunction with the really fast SSD no smooth workflow is guaranteed. 4K YouTube video (play in Google Chrome) overwhelm the processor and integrated Intel HD 5300. At least it came to stutter in my attempt. What has been of a great display, if it is unable to use the native resolution for videos.
2.) The pressure point of the keyboard is felt failed very badly. I would have expected similar quality in particular as the MacBook Air here.
3.) The battery life is far too short despite weak processor.
4) the unit is very noisy for the low power consumption and the resulting low heat (constantly running fan)
5.) The soft-touch surface is very sensitive to fingerprints. The same goes for the touchpad.
6) Lenovo provides extremely much "useful" optional software that is very cluttered.

Overall, a clear "unsatisfactory". The unit returns. I thought it may be similar to my previous favorite (Acer - here I unfortunately do not like the folding mechanism). I am absolutely disappointed with the device.