But TOP device (Android) Software problem!

Device: TOP.
Price / performance - true
Display - could be brilliant, but home enough for surfing. When streaming also acceptable.
Operating system: as usual.
Base: a unique solution from Lenovo - look super convenient for films and works without covers etc.

BUT

After two weeks of use, the device switched off easily. At first I thought of an empty battery pack, and put the device to the power supply. However, there was no battery meter, nor any reaction. Turning also was not working.
Only after 2 hours charging time and a hard reset (previously also no reaction with repeated attempts of a Hard Resetes) drove the unit finally back up.
The next day (the battery was 60% loaded morning) Yoga 2 in standby was lazy and idle on a Tisch.Bei reviewing the evening had it shut down again and was no longer to reactivate. After 1.5 hours charging time and hard reset a first sign of life.

So the problem was neither the battery nor the charging behavior, but on the device itself.
A call to Amazon confirmed my suspicion. It was followed by a replacement unit. (Unfortunately the same problem after 4 weeks)

Conclusion: Top unit, but useless by accidental shut-downs without spontaneous uses.
This was followed by the transition to a Yoga 2 with Win 8.1. Since 3 days it is stable.