Problems with feet and thread tension

The Overlock seam, which makes the machine, looks very good and is easily adjustable in width.
However, the machine makes a whole a "lightweight" (cheap) impression. For the price you can expect nothing else.
There were problems with the feet. The fabric could be foist difficult and after a few actuations of the lever for the feet to let this no longer use.
A second problem: Of the four threads were only three threaded. When trying also to use the fourth thread, I failed (a skilled seamstress). He constantly ripped off again, and the voltage could not be adjusted accordingly.
I sent the machine back and am going around in a higher price category, because I have the impression that it is precisely in the field of sewing machine much in vain applied time (and a lot of trash) can be avoided, if not "cheap" in the foreground, but a reliable quality - and has specifically in this area at a price.