Usability and format support: Full credit.
Supported USB disk: Full credit.
Whether stick, hard drive or mobile phone: If the device works on the PC as a removable disk, then the WD TV HD.
Playback Quality: Full credit.
(Tested on a good CRT TV, HD TFT comes yet)
Design and processing: Full credit.
My advice is, directly play the latest firmware and disabling, especially in the settings of the media library (more on that).
The reasons for the deduction of points are in detail:
The media library is practically useless. It takes a long time until a large hard drive has been completely searched and an index is created. In addition, some files will not play in Media Library is enabled, otherwise the run without problems. Especially bad is this shortcoming. Assuming you have no problems to click through a folder structure (one knows from Windows).
Was annoying that the WD TV HD some files not recognized after I had renamed the PC (it was to be displayed in front of the old filename, but than 0 KB file that you could not open). Even repeated separation of the hard disk and turn off the WD TV HD changed that assessment. Only after the files have been completely rewritten with a defragmentation (a different physical location on the disk were), they WD TV HD has recognized.
Photos are indeed well presented, but the zoom function is not particularly successful: Even if an image has a lot more than 10 megapixels, it will be displayed in full screen perfectly, when zoomed in one profits but not of the high resolution. At least not on a PAL TV. It looks as if the image was scaled to the PAL format, and when zoomed in only these scaled variant is enlarged to read instead of the corresponding image section of the image file. The Zoom-result is therefore very grainy. If one wants from a high resolution image to view a specific area on the TV closer, but you could cut those previously on PC and save it as a separate file.
There is no real "off" switch. All devices on my TV stands have a real "off" switch, and wasting no standby power. When WD TV HD I always have an extra pull out the power supply, however. A corresponding switch would only make the power supply sense since power supplies known to consume just like chargers even when not using electricity. A power strip with power switch is also not a solution, because you can usually do so only all connected devices zero current but remains single.
I have the WD TV HD already defended several times when here at Amazon a bad review is. For example, because of the lack of support for DVD menus: Such a feature was never promised. In addition, you are not forced to use menus, if you want to watch a movie ...
Nevertheless, I must admit that the device is not absolutely perfect. However, it is quite useful and provides for its low price a very high value in use. The drawbacks I have described can be bypassed / solve and possibly could even be resolved by a firmware update (except for the power supply).