I just got them. I think they work great when you have a light or medium flow. However, if you're like me who has one extremely heavy day, they leak a lot. The best thing about them is that you can have sex while using it. I use them on my lighter days and still use tampons on my really heavy day.
How are women using this for conception? They are inserting these after intercourse to help keep sperm close to the cervix. Combining this with laying down after intercourse is a good way to help keep sperm where they need to be.