If you dont mind paying for a Garmin, should you get one?
Advantages: semi-to-pretty accurate distance and pace, even when you're not running on the roads (i think).
Disadvantages: You may look and/or feel like a white-collar, spoiled runner with that extra gadget on your wrist.
You may miss the minimalist feel of going for a run without knowing too much about how far it is/was.