If you want an OTA HD DVR that has the guide info for FREE, you have to build it. Check out the forum here for PC based home entertainment. Basically you can run Windows Vista home premium or Windows XP Media Edition or a linux box with an HDTV card, forgot the name of the linux software but many people do it and enjoy it. Keep in mind that this sort of PC is full multi-media, DVD, MP3 and disk space is only limited by your wallet and imagination. What's nice is you have one single box where you can connect to the internet, burn DVDs, transmit recorded programs from one unit to another, watch it on your PC and do lots of things Tivo can't.
Actually, no. As I understand it, they do not plan on offering CableCARD support, or an ATSC tuner, so their product won't be a competitor to TiVo. I think the plan is for it to basically be just a box to connect a television to the web.
Also, my understanding is that their plan is to (like Motorola, Cisco, and now Samsung) partner with service providers (though in this case, with broadband providers), not try to navigate the circus of stupidity that comes from offering DVRs to the general public.
There is a more informative article here that explains a little about how Sezmi will use excess digital spectrum to deliver content to the box.
I can't list URLs yet but if you go to the Sezmi site and look under About Sezmi > News > Articles the Fierce Video article is the second one. They also won a TiE50 award for their internet infrastructure.