I had mine for 7 years and loved it to pieces. If we weren't planning on having another little one soon, I'd have another now. I had very little problem with insertion or removal; I found insertion a little bit more painful, but nothing that Advil wouldn't fix. My husband could feel the string, but that only really became an issue on the, uh, more adventurous days. My flow didn't increase, although I was slightly more crampy while I had it. It did take me about 6 months to conceive after having it removed, but my husband and I were also working on a cross-country move so I feel that the stress levels and the very limited amount of time together were the largest factor in that. It was also quite cheap when compared to other forms of BC. Granted that I got mine a decade ago, but without insurance it cost me $350 when it was inserted ($50 for the appointment and $300 for the IUD itself), and there was the cost of the appointment to have it removed, but that was it over the course of seven years. I can't think of anything else that would cost that little, especially anything nearly as reliable.
As I said, if I weren't planning on having another child in the very near future, I would get another one in a heartbeat. It was cheap (when factored over the time I had it in), low side effects, practically unnoticeable when I had it in, no worries about missing a pill or inserting a diaphragm wrong, highly effective, and the best BC I've ever used.