i used to fukk with Nike+ heavy back when it first came out and you had to use it with the iPod nano and put the receiver in your shoe for it to work properly. I enjoyed the Nike+ community because it was for people who weren't super deep into the running thing and the challenges were fun too. But the Nike+ system isn't for "serious" runners and I eventually switched to Garmin/Garmin connect which (while not perfect) will better serve the needs of those who run/bike/swim on a regular basis and need to analyze their data and manage it thoroughly.
When Nike came out with their GPS watch, I considered staying with them but it was their first watch, unproven among runners and it was $200 bucks, the same price as the Garmin GPS watch I got. The price has since fallen but they need a couple more years to prove themselves because Garmin is king in this particular arena.
But the Nike/Nike+ experience has improved, so use it to stay motived and keep track of your goals. You'll enjoy the Nike+ community since a ton of people are active and involved in it.