Hmmm, I didn't have a real good experience wit ProPrompter the last time I used it. Adding files was fine, just copy and paste. Getting it to sync with the iPhone was a bit fiddly but once we worked it out it went fine.
Controlling the scrolling was another matter entirely. We could only get it to scroll in one direction (i.e., couldn't back up a line if they wanted to stop and re-start in the middle of a paragraph) and couldn't vary the sped of the scroll (our work around was to scroll a bit too fast and constantly stop and start) VERY annoying, especially since I was also doing sound and sending a Skype feed back to clients in another city.