Strengths: Easy to use, as well as motivational, choose either your own playlists or songs, or aternatively download a Sport mix from iTunes. Doesn't have to have NIke Trainers as many companys have invented carrying devices for the transmitter.
Weaknesses: The website that you sync to after your run could be a lot more informative, but lacks good design. Try www.slowgeek.com for a great way to get more from your workouts.
Overall: If you like gadgets and recording all of your sessions this is a great tool to do the job. Seeing the miles clock up is very motivating.