I ended up going with advanced as it took into account other signs of fertility such as cm, opks (if using), and cp. FAM is based solely on having 3 consecutive bbt temps that are above the previous 6. Because I often had fall back rises on my chart (bbt would drop to coverline on 2-3 dpo for one day) FAM ended up not being accurate for me. It's a choice that's easier after a few cycles imo. I personally wanted ALL of my fertility signs to be taken into account so I went with advanced which was almost always right for me. FF has a nice explanation of all 3 methods they offer if you want to take a look at it...very helpful.