In reply to:
I record the 2 minutes prior to start and after ending, because I'm sure my VCR doesn't match up with the networks' clocks. But, I was under the impression (I believe someone actually told me) that TiVo couldn't do anything like that
Whoever told you that was incorrect. Also, the TiVo clock is automatically set by the server during it's call. (Replay probably does the same thing.) So the clock will be kept to the correct time. This doesn't guarantee that you will align with the network's clock but it gives you a better chance. I only have a couple of shows that I have to start early.
In reply to:
Another thing I remember hearing that I didn't like was something about TiVo's daily phone call - something about sending information collected about you to the server.
Both companies collect anonymous viewing information which they aggregate and sell.
TiVo has an official opt-out policy which can be done with a phone call. To quote
SonicBlue, "At present, users also cannot opt-out of the collection of Anonymous Viewing Data."
-Dylan