Strengths: Very Accurate, Flexible, PC Link, Fitness test, recovery state, and more features than you can wave a stick at!
Weaknesses: Times are rounded down to the nearest 1/10th of a mile when storing to memory
Overall: This watch has made the biggest single difference to my traning. No more training too fast or too slow. My running has steadily improved ever since I bought it. Don't pay £249 for it though, you can pick one up for under £200 if you shop around.