This is the first year I played a Yahoo league for years. My impression is that it's not very good. Yahoo automated projections, especially weeks out, look pretty bad. Even the point projections for the current week often look wrong, and can contradict the "expert" rankings. And it just seems to rate a trade based on the impact of the starting lineup. If one team improves a starter and the other improves their depth, even with no loss of scoring for their starters, Yahoo makes it look like the first team is ripping the second one off. Things that ranked fair at any other fantasy football site, where some thought is put into player value and team strength, can get made to look awful with Yahoo's tool. But you can't ignore it, because the other party getting your offer will certainly click on it.