RunnerGirl77 says:The Nike+ system is based on your stride length; basically, it's a fancy pedometer. The Garmin Forerunner 305 is GPS based. Rather than deriving it's information based on each foot-strike, it gets its information from satellite reception.
Now, I got into GPS units through geocaching, and I've owned a number of different units for hiking before getting the 305 for running. That said, you can see how I can compare it to other GPS units. The SIRS high-sensitivity receiver is very good at keeping "in touch" with the satellites, even when under tree cover. I went the "extra mile" (so to speak), by marking waypoints with the 305 and my best hiking unit, and found the accuracy of each waypoint to be within 6 feet of accuracy.
If I'm sluggish, my stride is sometimes shorter. That's my biggest problem with pedometers. Most of the posts that I've read about the Nike system report some discrepency with speed and distance.
The GPS system isn't for everyone. There will always be somebody who it doesn't work for. I've also met lots of runners who use it strictly for time and distance, and don't make the most of the routing and waypoint features. There are also those who use it to it's fullest potential. If you think that the accuracy is important for you, then it may be worth the investment for a GPS-based system. I love mine; I defy the Nike+ system to guide me back to my car, as the Garmin did when I got lost on a trail system one time.
That said, I would suggest going for the 305 rather than the 405. I've read a lot of posts from people who have "bezel" issues with the 405. Nobody I've talked with has liked the new software for the 405. Luckily, there are other alternatives, like SportTracks.
