I'd say they are. For those in the front of the plane, it's a quicker way to get off. And the exit rows have the extra legroom. Can't really think of an instance where the non-preferred seats are better than the preferred (except for 26A/B/C on the MD-88s, which are exit rows with full recline that are not preferred; 25A/B/C, exits with no recline, are preferred...go figure).