jogging stroller ?

stringbeanarina

I recently finished the Couch to 5K program and ran my first 5K race. My problem now is my babysitter is unavailable to watch my kids while I run. I am looking into getting a double jogging stroller.

My main question is about the front wheel. On some I see the front wheel is fixed and on others it turns freely. What is the difference? Is one better for one running terrain than another? I will mostly be running on trails at parks. 

Sorry to post and run, I just got a call and need to head out the door, so TIA!!!