I have a ReplayTV 5040. What I like most about it:
1. All 5000 series Replays (not sure about the 4000) try to detect commercial breaks while they are recording. They write out an 'event' file with this info but only the 50xx models give you the option to automatically jump over these breaks during playback. On the 55xx series you can manually do it by pressing the Right-Arrow when a commercial starts. I think they call this "scene advance". The remote also has a 'skip ahead' button that will jump ahead 30 seconds at a time.
2. If you connect the ReplayTV to the Internet over a home network to get the channel info, you can load free software on a networked PC to make it 'look' like another Replay unit. You can't schedule recordings on the PC, but the PC can be setup to automatically download and delete shows from the Replay thus preventing the Replay hard drive from getting full. Again, the PC looks like another Replay unit so when you want to watch those shows you can just tell the Replay to play them off of another Replay unit (which again, is your PC). You could also hack the Replay to replace/add a hard drive but I find this solution to be more than adequate.
3. Another free program can be loaded on your PC to allow remote control of the Replay from a web browser over the Internet. Kind of handy if you've forgotten to schedule a recording that will occur while you're at work.
Both programs I mention above are
not from DNNA so they aren't 100% trouble-free. Also, as someone else mentioned, the 50xx models allow transfer of shows over the internet and this feature is not available on the 55xx models. Not of interest for me but some might miss it.
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