I use it again the old ...

First of the positven things:
+ Precision adjustment of the cutting length
+ No accidental adjustment of the cutting length
+ Sharp blades
+ Calibrates and handy
+ Very good battery life
+ Acceptable volume

So all in all a well thought-out device, but unfortunately I'm getting so not so good cutting performance as with the old (10years old!) Cabled Phillips-hair cutting device in which actually the blades are a bit dull and I actually wanted to replace.
I must say that I cut my partner every 3-4 weeks the hair. And I do not mean anything to a length but a morderner, sporty cut as the hairdresser. Anyway, I manage not with this device, to be phased out as usual the sides and back of his head clean without edges. In addition, the sectional image is unclean remain so always longer hair stand between.
In a direct comparison is then noticed that the hair trimmer is not as good on the scalp slides like the old man.
I'm going to buy spare Lingen for the elderly and the QC5390 / 80 sale. Since the return period has expired.
Too bad.