Nice and quiet, but still had problems with the suction power

I use the vacuum cleaner now for over half a year and have to say that I would buy him again. The initial cleaning efficiency was very good at the first time. He sucked pleasantly quiet and I was surprised how strong the suction power was still. I also found it interesting to see swirling around the dirt sucked in the transparent container.
Meanwhile, my enthusiasm has waned but. The simple reason is that the cleaner appears to have significant problems with (long) hair. This suction force within a very short very strong. To its knees At the beginning of a room is still OK performance, but decreases after a few minutes from the extent that, for example, a raisin is not sucked by the flat bottom. However, the collection container is nearly empty. Taking it out and engages from below a frustoconical filter, so sitting on the already complete. The hairs form a network on which sets of household dust and the sucker paralyzing.
So I have now almost permanently clean this place in order to suck at all reasonable can.

As I said, again I would not buy the sucker.