It would also probably depend on how 'big' you are. I've never had a problem with seat width, neither has my wife or children, hence we choose based on cost most of the time (as paying for flights for a family of 4 isn't cheap in the first place). We're not particularly fussy flyers.
If the flight was longer than, say, 5+ hours then I'd start looking at seatguru, for things like IFE, comfort and so on if I was taking the family away.