The only thing more advantageous is the weather. schools from college to pre-k are out 2 weeks or more (in the US at least) at xmas. They're out memorial day in may, school tends to end for most places in june, so then you've got no school to compete with. You could argue the colder weather helps it because going to the movies has fewer things competing with it when the weather isn't cooperative (i.e. when it's cold).
What do you want as a studio? Release in warm weather when schools in session for the first 3(ish) weeks of release or December when it's colder, but schools OUT the first 3 weeks? I'm not saying I know that exact answer, but for a general movie, the more chances for your audience to get in the door, the better. This is likely to be a rarity these days with a staying power of more than what seems the typical 3 weeks at which point it's an after thought.
Well, the answer is in the facts. The two biggest films of all time were released in Dec. The reason Dec. is likely better then May? You don't set box office records selling tickets to kids, you do so selling tickets also to women and families. That's why Avatar and Titanic reign supreme, the demographics were very broad. Dec. provides a very family oriented time of the year. The numbers don't lie. I think TFA has been crafted to have that kind of broad appeal. I'm very happy they have a strong female co-lead. From the spoilers I have read this film has a lot of heart and I hope that will bring in more then just the young male demo.