IME it makes no difference. With the design of the Tele bridge there is only about one inch of string behind the saddle on a top loaded bridge. I doubt that is enough to make any difference in feel, and as I said, I don't notice any difference.
I have two string through Teles, and one top loader. I find absolutely 0% difference in string tension or feel. As far as sound, they are all slightly different, because they are different guitars, and have different pickups, but they all sound like Teles.
I've already posted this elsewhere, but it seems appropriate for this discussion. This is my top loading Esquire. You tell me if you think it is lacking in tone or sustain.