Ive had 9 and a defill. The defill was fine and 7 fills were totally ok and pain free, two of the others were painful and they had to use 5 or 6 needles in one case because they couldn't find/get into the port.
My first one was one, although it was the pressing down which hurt more than the needles, I don't find even if they cannot find the port that the needles hurt.