I voted for Teens because the game puts such an emphasis on socializing and then makes it nearly impossible for teens to socialize with each other.
My teens are at school from 8:00 AM until 3:00 PM so it makes no sense to me that the teen population is out strolling around the neighborhood from about 10:00 AM until about noon when my teen isn't at home. Then they disappear until late afternoon when they can be seen out strolling again. The problem is that if my teen tries to chat with any of them, they will only stop for a few seconds and then walk off.
On the other hand, my teens end up meeting all of the young adult and adult pre-made Sims by simply dancing at a club. In the new game that I'm playing right now, my teen "met" Candy Behr on the dance floor and now she bugs him every day with an invitation to take her somewhere or visit her at her house.
Teens sometimes get a prompt to bring someone home from school. This is fine as long as the teen isn't entering a phase or has a mood swing underway or has chores to do like take care of the garden, isn't ready to pass out from being tired or very hungry.
It's almost like they're not really supposed to make friends.