I've had a few, I think they were all beneficial, especially the one that ended my second looong labour (19 hours at that point); labour had stalled because after my coccyx got in the way then my cervix formed a "lip" that my DS couldn't get through... it was excruciating when my Ob maniplulated the lip of my cervix but things happened fast after than (not too fast to tear luckily) and the pain was lessened and I actually started to feel postive about being able to push (I could feel it was achieving something). I've also had to have my membranes ruptured (foetal distress) which showed meconium... I'd be annoyed if I'd have to have too many internals but so far things have improved because of them. I'd definately dislike and possibly refuse to have an internal early ultrasound though.... never had one but they sound shocking.