The number of people using OTA is hard to pin down. Depending on who you ask, the number can be anywhere from about 10% up to about 40%. It also depends on whether you mean "exclusive" use of OTA or in combination with other sources of programming. Nobody has a definitive study of whether OTA usage is growing, shrinking, or staying the same.
In any case, there are definitely tens of millions to hundreds of millions of people using OTA TV in some way.
You have to decide for yourself what role OTA will play in your setup.
The nice things about OTA are:
- It's free (or at least an order of magnitude cheaper than pay TV if you count the investment in an antenna)
- Most people can get several of the major broadcast networks/affiliations like ABC, CBS, NBC, Fox, PBS, CW, ION, MyNetworkTV, ThisTV, Universal Sports, etc.
- The picture quality of HD channels is outstanding (often better than the HD channels on cable and satellite)
- Some stations have extra programming streams (sub-channels) that are not available through cable or satellite systems
The caveats that come with OTA are:
- You can't get pay-only channels like HBO, ESPN, Discovery, Pay-per-view events, etc.
- Some people are not in a good location to receive OTA broadcasts
- Many people simply aren't aware of, are mis-informed about, or are intimidated by OTA TV. Very little attention is given to OTA services in comparison to the big-budget ad campaigns the cable/satellite operators use to get people hooked on their services.
If your viewing priorities primarily consist of network television (ABC, CBS, NBC, Fox, PBS, etc.) and movies, then a TiVo + Netflix combination should fit the bill nicely.
You can also consider companies like Hulu, Amazon, Crackle, Pandora, YouTube, and other internet sources for additional content and variety.