I have the Clear Plan Fertility MOnitor, I bought it last August after I had a m/c in April. I used it for about 3 months and i did not get preggo. THen I left it and began using it again in January for two months.....still didn't get preggo.
I think it is probably a good tool to use, but it really wasn't worth it for me. Currently my dh and i have stopped ttc, but I don't think I will be using it again.
I have read numerous success stories on their website though, I just may be an unusual case
Edited cuz i can't spell!