OTA should beat the quality of just about any source other than perhaps some bluray discs. See.. they've got 19mbits/sec to play with on an OTA physical channel, far more than cable or satellite, and definitely way better than standard DVD or most kinds of legal downloads.

Rather than pay a monthly Tivo fee for free OTA, just dedicate a PC with one or more ATSC tuners to the task, and install SageTV or a free equivalent (BeyondTV, MythTV, GBPVR, etc..). A modern (though low-end, eg. Nvidia GT210) PCIe video card is required for this method, though.

Go to tvfool.com, enter your zip code (or better yet, street address), and see what it says. It will give a pretty reasonable indication of how much OTA you can expect to get from your (almost) exact location.

Cheers