I don't have a Joovy. I will give my two cents though. I would get the Sit & Stand Dx or whatever that can have 2 seats OR a bench and a seat. I was really nervous having my 2 yo on the bench in the back (mine does not convert). That said, both my older girls have fallen off the back of the stroller horsing around more than once.
Re: Joovy Caboose Ultralight vs. Baby Trend Sit and Stand?