The player is DLNA-compliant and supports most formats but importantly not DivX. If you're a fan of SACD, the 5100 will output DSD natively via the HDMI output. Unfortunately, it isn't able to play back DSD downloads, despite.
The player has an onboard browser that is controlled via the remote (yech!) or with the TV SideView app (above). Sadly, the browser doesn't support Flash.
For the last few years even the cheapest Blu-ray players have had high-level playback capability and there has been little to separate many of them. The Sony performs similarly to its competitors in both synthetic and real-world tests. Only in the film tests in our synthetic HQV test suite did it suffer from any aberrations. The test consists of a slow pan past a football stadium and in both the 2:2 and 3:2 pull-down sections the Sony exhibited more moire than the , and a little bit of judder in the 3:2 pull-down test. While there was some processing happening neither test could be considered smooth, so it had to be marked as a fail.
While the Panasonic did have a strange problem with one of the Chroma patterns in which it initially failed but on restart it worked, the Sony passed the first time. In real terms this means the Sony is unlikely to exhibit combing on red colors during playback, but this is more a problem for analog connections -- something this player doesn't have anyway.
But those minor failures on synthetic tests just didn't show up much when we looked at actual program material. While there was some "shimmering" in the horizontal lines that form the stairs in the cocktail party scene from "Mission: Impossible 3," the image held and didn't revert to moire. DVD upconversion was also a highlight, with no issues in the "Star Trek: Insurrection" opening scene. The camera moves around a rural setting and on inferior players the images can revert to moire as well, but not here.
Getting back to the aforementioned "Super Wi-Fi": is there anything to it beyond the gimmicky name? I tested it against the Panasonic and found that they were about as super as each other -- "super friends" if you will. I tested the players in a couple of different network environments and found that the wired and wireless connections operated at very similar speed, just managing Netflix's recommended 7Mbps for HD content on the browser-based speed test SpeedOf.Me.
By comparison our wiredTV got an average of 19Mbps on the same broadband connection. The reason for the discrepancy could be down to the difference in the implementation of the onboard browsers and the amount of bandwidth the device assigns them. Switching to more real-world tests, the image quality of the Sony BDP-S5100 was perfectly acceptable on our "Lost" TV show test, with no sign of MPEG blocking or softness.
The DLNA client on the Sony isn't great for playing music thanks to its lack of playlist capabilities -- you can only play one thing at a time with no browsing in between. For example, if you are playing an album, hitting the back key to browse your collection immediately stops what's playing -- annoying. The lack of DivX may also be a limiting factor for people with large video collections.
While there is very little to differentiate most Blu-ray players, there were some subtle differences between the Panasonic and Sony players. For me, the reason to buy the S5100 is that the user interface is easier to use and there are no ads. While the Sony doesn't offer the ultimate in picture or build quality, it's a solid all-rounder and arguably a better deal than a Roku 3 if you still depend on disc playback.