We rarely go out, so I'd have to say I'd prefer to have dinner out. Dinner at home could be nice but there is an ominous feeling about the dishes when we're done eating. Dinner at home seems like it's a rush sometimes, a rush to get the kids to bed and start cleaning. A rush to get everything done so I can relax. If we go out, someone else is serving me and even though I still have to tend to the kids it is more relaxing. When we're out, I don't have to worry about the mess until we get home.
Another thing is we get stuck in ruts, eating the same meals. When we go out, I get to order seafood (dh doesn't like it, so I never cook it). We get to have something different than usual.