If you read through the comments already posted (and there are many), you'll see that most people are very strongly polarized... people either love this show or hate it.
I, for one, am somewhere in the middle of the road about it.
It is heavy-handed. It takes an 'issue of the week', and involves each member of the family in some aspect of that issue... fidelity, drug use, abstinence from sex before marriage... then wraps everything up in a nice neat package before the end of the episode.
The way the issues are dealt with are both shallow and heavy-handed. You never have any doubt in your mind what issue the writers are bringing up this week; you never have any doubt what they thing the "right" thing to do is.
At the same time...
We're looking inside of a family that seems to genuinely care about each other. There's a father who's involved with his children, siblings who look after each other, and a mother who obviously loves her children... and her husband, even after seven children.
Yes, Matt needs a punch in the nose. Mary could stand a valium perscription. Lucy needs a little more maturity. And so on. But...
But I keep watching this show, episode after episode.
And I'm not entirely sure why.