Is treadmill running better than no running at all?

How much better is it to run out on the road or on the trails versus running on a treadmill? If I cant manage to run outside can the treadmill be a suitable substitute for this? Coach Parry answers today's question from our member's forum about running on a treadmill, he talks about how to get the best out of running on a treadmill if running outside is not an option.