I had it done twice. First time it just felt like a normal internal exam. Second time it was more uncomfortable than the first but I don't remember it bothering me by the time I got home from the appointment. Also, later that night I went into labor so...
it was definitly uncomfortable, but I wouldn't say it was that big of a deal. I was talking to him through it and it only lasted a few seconds, and then I cramped immediately, and then a lot the next day. Its really not bad.
I would say it was more uncomfortable than a normal internal, but I wouldn't say it hurt. I had it done on Monday and had lots of cramping and such afterwards but no luck with going into labor yet.
Re: those who have had membranes stripped