Here's what I looked for in my media player:

- Can play MKV, MP4, and AVI/DIVX/XVID files
- Can output Dolby Digital 5.1 and DTS 5.1 audio
- Can downconvert DTS 5.1 to 2.0 stereo (when not using a 5.1 setup) - WDTV couldn't do this at the time I bought my Seagate, now it can
- Can read media as it's organized on the hard drive instead of just throwing everything in an alphabetical list (murder on TV show files)
- Can output 480i composite/component, 480p/720p/1080i component/HDMI, and 1080p HDMI (as a bonus, it can output 576i/p and 720p50/1080i50/1080p50, though I can't really use that except on one friend's projector - nice for watching Doctor Who, though)
- Can handle (and easily switch between) multiple audio and subtitle tracks

...And that's pretty much it. So the WDTV and Seagate players both do pretty much exactly what I want it to do.

Things that mine can't do that I wish it could:

- Play a forced and/or default subtitle track without me having to turn it on

So, for me, except for that last annoyance, the WDTV or Seagate players are just fine.

What added benefit is there to the Popcorn Hour or Playon!HD Mini? What's better about the menus, and what other/better features than the above do they have? Can they do Dolby TrueHD/DTS-HD? 7.1 output?

Not trying to say "mine's better," I'm genuinely curious because my Seagate's getting a little old and I'd like to replace it in the next year or so, and I want to know if it's worth it to get something more expensive and why it is.