I KNOW!!!! Well - so mymonthlycycles has the most data, but not temperature data. I've been tracking my cycle lengths and bleeding through mymonthlycycles since I went of BC last December. BUT - that also means that it has those long cycles before I started the herbal supplements and stuff that could be skewing it's "avg cycle" predictions (and why I think I missed my O date last month because I didn't get as in depth with my tracking until it was too late I think).
Ovufriend moved my O date after I put in a few temps post O. So that was weird - it thinks I o'd two days later than FF has my crosshairs, and after I got a negative opk. So I'm not really sure what to think about that - but I know that's why it has my cycle start date two days later. So Ovufriend and FF have the same data, but different interpretations.
EDITED TO ADD: I fixed one temp on my Ovufriend chart, I didn't realize there was one discarded (the temp dip right before O) so now it's in line with FF and they both think I'm 2 days late.