Pros: Excellent picture and sound quality, networkable, streams from key services
Cons: Limited control of audio output, does not play AAC codec
As a low priced, no frills bdp, the S580 also offers a few features that are usually found only in mid-tier and top-tier players. For example, it can play MP3 encoded and uncompressed (WAV) music, as well as movies of various formats, from any DNLA or uPnP media server over your home wifi network. It can also play hi res uncompressed (WAV) music -- up to 192 kHz/24 bit -- from a USB flash drive. (If you try to stream hi-res music, you will be rewarded with an awful pulsating sound). When playing music or streaming video or music, the current bitrate can be displayed, from which you can extrapolate your sample rate and bit depth.
However, there are some features missing that will remind you that this is still a budget player. When watching Blu-Rays, it won't tell you what audio codec it being used, so there is no way to verify whether you are really playing those awesome Dolby TrueHD and DTS-MasterHD tracks. The music player does not recognize several important formats, including FLAC, AAC/ALAC, WMA, or really anything except for WAV and MP3. The BDP also lacks the extensive control over audio output for which the Sony PS3 is famous. Your choices are 2 channel or 5.1 (no options to control passing various bitstreams or PCM, or to select sample rates). Construction seems rather flimsy despite light aluminum case. I'm not sure if it is actually flimsy -- it just feels that way. (It differently won't pass a knuckle test.) Though it has 2 USB ports, devices for some reason are not hot-swappable. Finally, unlike the PS3 it almost never receives a firmware update, suggesting that Sony is not very motivated to support the player. This is especially frustrating because several of the issues mentioned could probably be fixed with a firmware update.
As a parting thought, in the 2+ years that I have owned this BDP, I haven't had any quality control issues. That counts for something.
Overall, the S580 is a decent budget blue-ray player, but it doesn't compete with players above its price point.