Not currently using it, but I've done it both to avoid and to conceive. We went almost 2 years without a pregnancy. It's effective as long as you're charting accurately. I would recommend back up birth control for the first 3-4 months until you learn how your own cycles are and when you can better expect ovulation to occur.
Yes. I have used it successfully for the last 3 years. You need to really know your cycle. There are some great books and resources that can help.... I'd have to go back and check my records to find them (now it's just wired in to my brain) but would be happy to do that info for you if you'd like. Email me and I can get that for you...t.