This review focuses on MediaLink's ability to handle mp4 video. Other video formats native to the PS3 work pretty well if one chooses to forego the transcoding option. MediaLink handles audio and pictures well too. But the PS3 has a bug in its DLNA client code which forces enormous bandwidth utilization when streaming mp4 files. This causes stuttering for many users, and Nullriver is following in the footsteps of other DLNA server vendors by introducing forced transcoding of mp4 files. In a way this is unfair to Nullriver -- the bug is Sony's. But since Nullriver is trying to address it, we should feel free to note the result. And the result is poor.
The UI now allows one to "force" transcoding for mp4 files. If one chooses to do so, the Mencoder options kick in. However, some options are ignored (such the bandwidth cap). At times, the audio is out of sync. If one uses the PS3's scene search feature and selects a scene, the screen goes dark for over 60 seconds, and then plays video which does not match the selected scene. Fast forwarding and rewinding hardly work at all.
If one deselects the option of transcoding mp4 files, most features start working properly, and the audio sync problem goes away. The PS3's bandwidth bug kicks in, but if your network is speedy enough this should not be an issue, and it hasn't been. But now, after a period of time, a network error shows up (esp. if you try to fast forward or rewind) and the video stops playing. This never used to happen with version 1.72.
MediaLink has a great UI, probably the simplest, clearest, and most intuitive of all DLNA servers. But if you want a DLNA server that simply works, either with transcoding or without, PS3MediaServer handles all the scenarios I complain about above perfectly, and it's free. I want to see MediaLink reach parity with PS3MediaServer's ability to stream mp4 video. That alone might justify its cost. But this beta is nowhere near that goal.