I was even on a low-cost player from China (the "steal me quiet, does not bother me really Player", which I had bought once for the Fittnesstudio :-)) excited by the sound, the noise that got there, came from the player itself. In a better player this were no longer available.
My explanations for poor grades:
1. It is remarkable that here some reviews are identical, also of the texts. Whether someone tried the competitors to make a bad thing?
2. It is not impossible that there are really bad copies that are in circulation
3. (seems to me a crucial point) you should have reasonable sources. 128 kbit / s MP3 sound "good", so long as the speakers and / or headphones are good nothing.
And you have a good sound system, you realize that it hooks suddenly. But that is not the fault of the speakers or headphones, but the source files. Degrees in the height range, it comes then to Klipping, sibilance, etc ...
I have been actively involved with music, at first I had ripped many disks and CDs with 128 kbit / s, was indeed long standard, I was also recommended by many sides "128 kbit / s is sufficient".
That does not exactly! After I added myself here quite a quality monitoring system for home recording, I realized that with many pieces of music especially in the altitude range problems were present. Problems that I could not hear in advance (on the old boxing). Eben said sibilance and clipping. It is important, therefore, who wants to hear not only "radio quality", but more like to experience that should rip with at least 192 kbit / s.
The mechanical problems I tell erstmal nix, because I still had problems with keien. To consider admit, however, that there always play together two components, so it can also sometimes the socket on the beloved Apple player be.