They are beyond limited. I have an older Pioneer 420 DVD recorder/hard drive recorder that only has an NTSC analog tuner, and I've been wanting to replace it with an ATSC/QAM Hi-Def unit. As far as I can tell, your only choices are a TiVo HD (which can't record DVDs) or a Philips unit that has an ATSC tuner but only records in standard def. ARRGH!