I have used TiVo in the past (cable card setup - it also worked with OTA), my problem was not only did you have to invest in an expensive DVR + subscription service, but each and every TV had to have the TiVo Mini ($199 device that basically only displays Hulu, Netflix & TiVo DVR), and you can’t use streaming devices with it. The more TVs you have, the higher the price.
Tablo is by far the best DVR out there, when considering costs (startup and subscription) for OTA.