I was thinking it could depend on the ordering of your list, and the position of the list.
If your list starts at the first item, and has not moved, i would add at the top, as the end of the list is possibly out of sight. So the users gets immediate positive feedback that the item is added to the list.
But in that case, since the items are ordered as they were added, i would reverse the order and show the newest items first (so that the list keeps the same appearance if you would refresh or return to the application later).
Now i am not sure what would happen if the user has scrolled through the list, and the list is positioned for instance at the end (and the first items are out of sight). I guess I would still add at the front, and position the list accordingly to make the new item visible.
If the order of the items is important, and you want to keep the same order, i would add them at the end, where they would be located anyway (e.g. after refresh); and then jump to the position of the newly added item, to give the visual feedback.
Since jumping to a position is a big change, the addition of the new item might not be immediately clear, so maybe using a fading highlight.
Using a fading highlight to indicate the new item clearly might in any case be a good idea.