Strengths: Taste great. Easy to eat, soft and moist. Good flavours.
Weaknesses: My stomach simply can't take them, after an hour of running, I NEED A TOILET!!!!
Overall: If you can put up with the stomach troubles until you get used to the - after 2 weeks I still wasn't, then they are great, good energy release, taste great, loads of flavours and not too expensive.
Strengths: Easy to use, Power song is a great feature, The online site is awesome to keep you motivated, Easy to calibrate for super accuracy, but without calibration it is still within a few % of an actual distance.
Weaknesses: Unless you have the Nike+ shoes you can get distracted by thinking the sensor has fallen off your foot.
Overall: Highly recommended. I run in Asics gel's so no hole for the sensor, so I purchased a small sensor pouch from e-bay for a couple of quid that goes straight onto your laces.....job done and sorted. Never run without it. The online Nike+ site is great, loads of worldwide challenges to join and compete in that really keeps you motivated, even in the cold winter months.