I think Philips/TiVo's refurb department is just totally sub-par, as in, they don't bother to test their equipment. My refurb TiVo came with bright green line through the picture that only a color-blind tester could miss. Still, that worked out fine because Tivo replaced the supposed 14 hour unit that I purchased with a 30 hour one, and at the time, that was a big money difference. So for the cost of a little hassle on my part I got a VERY good deal.
With other things like hard drives and computers, I've had great luck with refurbs. It just would have to be a good deal (I'd say at least 30% savings or more) for me to do it. If it was like $200 off a $2000 panel I wouldn't bother.
-- Rob