American Dad is better, but because they're both made by the same person, they're both good.
I like American Dad better because it doesn't have the stupid "Remember when we..." jokes and the characters are better developed and some of the characters in Family Guy are just plain unbearable. The Giant Chicken is stupid IMO. American Dad still uses violence, but not excessively.
Mostly, Family Guy has too many unnecessary segments. Most of their jokes have been in every episode, like Meg being unloved, peter being hurt, Giant Chicken etc.
American Dad also has story arcs sometimes, spanning multiple episodes. Stan and his family just seems more like a normal family than Peter. They are also better at pulling off multiple plot lines in one episode.
I think it's just more polished.

I hear that.

I was kinda amazed that they postponed both of the christmas episodes for a week becasue of the schoolshooting and what not. I thought they must have been really bad as in "you think thats bad, remember when I was a NRA spokesperson at that kindergarden?" But nah, they were just pretty lame christmasepisodes.

Both being made by seth,
I have to say American dad is more unique than family guy now,
Family guy's humor is dry and stale now,
While American Dad's humor is still fresh

I hate Family Guy only watch it when there is nothing better on. Yet I love American Dad I don't really get it. Well that's not true. I don't like that half the episode in family guy are a bunch a jokes that have nothing to do what's going on. There been many times I forgot what was even going on in Family Guy because they pull away from the story. I think I get frustrated because most of the joke are a bunch of cheap shots of public icons that most the time really don't make sense. I use to like Brian because he was smart and witty. But after he proclaim himself as an atheist he just became a big headed jerk. Also Quagmire makes my skin crawl. While American Dad still has the randomness about it but it's still linked to the story line. Plus I love Roger even though he's a big perv like Quagmire and tends to ruin peoples lives just because he wants to throw a hissy fit. There is just something about him that's kind of adorable.

I rate them both as the same.

If they were showing on TV at the same time I would probably lean towards Family Guy.

Purely because I think it has just that little bit more humor in it.

But generally speaking I will only watch either of them if there is nothing else on/ I have nothing better to do.

I like them both equally but who else thinks it'd be funny if they did a cross-over like Peter and Lois with Steve,Haley,and Roger and Stan and Francine with Chris,Meg and,Brian.Or maybe Peter with Francine and Stan with Lois lol.