Strengths: Excellent value for money, the garmin 101 helps you to keep a really detailed log of your running and progress that you make. I also find the fact that it stores your total milage really helpful as I can tell at the push of a button when I need to be changing my shoes as its advisable to do so every 500miles. I have found it really beneficial in recording my results/slipt times frmo previous races so when I return next year I can gage how much quicker (or slower!) my pace is!
Weaknesses: The GPS sometimes is quite slow to lock on, so I often have to stand around waving my wrist in the air for a few minutes if im running on a cloudy day! Having to use batteries doesnt really effect me as I have got into the habit of using two sets of rechargables which I alternate after each run
Overall: By far the most useful running item that I have ever brought. Ive had mine 18months now and I never run without it!