"I have 3 other media players ..".
You are not comparing like with like. The Digital Living Network Alliance has precise specifications for each DLNA class of device.
A DLNA video client, for example, is only required to play MPEG-2 - the server being expected to convert other formats (unless the client tells it that it supports them).
However I do agree the client has faults, for example,
- Not offering a choice of audio track where more than one is present.
- Errors in enumeration of a folder.