double stroller ?

Kaitlyn • 👩🏼👶🏼🧒🏼👨🏻🐶 outnumbered by boys. Mommy to Lucas & Logan 💙
So I'm not sure about the double stroller.
 I know I'll need it but I'm wondering what everyone's experiences are with these different kinds of double strollers. 
Once baby 2 is born my son will be 16 months 
the side by side stroller or one in front of the other ?