I have used it, it really helps some people. However, you have to really monitor your use and make sure that you don't get constipated. They pulled Lotronex off the shelf before because people who didn't need the medicine were taking it and got bad blockages. So if you are on it and you feel like you are getting constipated, you need to cut back a bit so you don't get blocked.
However, they also have a lot of restrictions on taking the medicine now. The dr has to have forms signed that allow him to prescribe it and you have to sign paperwork. Then, you can only get one month at a time and you have to go back to the dr every month for more. At least that's the way it was a while back.
Good luck, I've got an appt monday and I fear that a colonscopy is in my future too.