I researched them and decided on the Baby Jogger Performance Double. I did look into BOB strollers too, but the Performance Double fit our needs better. I trained for marathons with both kids in it. It has a weight of up to 150lbs and fits my very tall torso'd son. (He outgrew the Britax Marathon before 3 due to torso height and is currently on the last setting on the Britax Regent at 5, to give you an idea of his torso!) Also, I could start using it when a baby was only 6 weeks old. And it steers easily with kids of different weights. Currently, my son is 50lbs and my daughter is 25lbs. I love the double canopies that can be adjusted for each child seperately.
I think our stroller cost $400 when I bought it 2.5 years ago.
*The "best" stroller is whatever stroller works the best for your situation. There are too many variables to decide what the best stroller is for everyone. Though the BOB strollers are great, they weren't the best for our situation.
My Baby Jogger tracks straight, is comfy for my 4 yo and 2 yo, mom uses it, the sitter uses it, I use it. Worth the money. I used an ebay store and bought last years model at a good price.
Oh- I can fit it in the back of my subaru (and I have my seats tethered) and it fits in the back of my Honda O also.