Replay's scheduling paradigm is frustrating and requires constant maintenance if you record a lot of programs with potential overlaps.
If I'm not mistaken, the 5000 series of the ReplayTV now includes a conflict resolver to warn you of overlapping programs scheduled for recording, as well as the ability to record a few minutes prior to the start and after the end of the program. I find that very useful, because not everyone's clocks match up.

And if you have DirecTV then it's a no brainer.
I haven't even looked at DirecTV yet. I'm just looking for opinions on the DVR units themselves. And as I and others have mentioned earlier, many popular shows have repeat days or times, so a 2nd tuner isn't really important.

I still think I'm leaning towards the ReplayTV at the moment.