When we got FiOS TV, I ordered a refub Tivo HD. The box was dented, scratched and filthy..looked like someone had pulled it out of a garbage can. I sent it back and Tivo sent me a replacement. This one was a good shape, but it had what I believe to be a buffer problem. Tivo send me a replacement remote (which I knew wouldn't work) and I eventually retured the box and terminated by trial service. My first Tivo HD experiece was not a good one.
Anyway, a couple months later I found a brand new TivoHD online for $208, so I purchased it along with a My DVR for $109. While I can certainly recommend the TivoHD (almost as good as the 622/722), I cannot recommend buying a refurbished unit based on my experiences. I recommend spending a few extra dollars a buying a brand new unit.