Since I want to avoid all the flickering that occurs when I watch Netflix on my Premiere, I have set the video output from the TiVo at 1080i, and no other (my Sony A2000 SXRD TV does not do 1080p/24, only 1080p/60, so Netflix doesn't play well with it). That fixes the flickering.
I don't want to restart the 1080i v 720p arguments, but what do I lose when watching cable stations delivered to me in 720p which are then converted by the Premiere and output at 1080i?
Conversely, if I set the Premiere output at 720p, I assume it will convert a 1080i signal to 720p, then deliver it to my TV, which then converts it to 1080p/60. Is this the better way to go?