No it isn't. To many people have boosted K/D ratios. Its unreliable at best. There might be a few who have legitimately earned their K/D but the vast majority got boosted because they wanted to earn some achievement or some other bullshit that they couldn't do on there own. It pathetic when I can go into a lobby and see a person with a 3.0 or higher K/D and they bottom out the leaderboard at the end of every game. I don't use K/D to determine a persons skill level. I go based on what I see in actual gameplay.