If the extraction of shows from the unit to your PC is at all important to you, I cannot urge you strongly enough to buy a Replay. Tivo is great if you want a mindless experience and a pretty GUI experience, but if you are a "nuts and bolts" type of person (I would venture to say most Empeg owners are) then Replay is for you.
The best analogy I have heard lately is this:
"The Tivo is the Mac of the PVR world, where the Replay is the PC equivalent."
I think that statement is dead-on. If you want to tinker, or don't want to become a command line ninja, then stick to the Replay. I am much happier as a Replay owner from an extraction and show manipulation perspective.
Just my opinion...
Rob