A big factor to consider is whether you want the front wheel to pivot. Pivoting wheels are easier to turn in a small radius. If you have a fixed front wheel, you have to pick up the front wheel in order to make a tight turn. The fixed front wheels are great for running, but they do not transition to inside or crowded spaces very well (malls, stores, festivals, etc.).
I have a Baby Jogger Q series double jogger. It was pricey, but I love it. Both my husband (6'4") and I (5'8") can push it comfortably. It holds up to 100 pounds. It folds up easily to fit in the back of the car. It does have a fixed front wheel, so I have a different stroller for non-running activities. I agree with the mom who mentioned that joggingstroller.com is a good place to research and buy a new stroller.