Instruct: Classify Amazon reviews into positive or negative sentiment
Query: Massive achilles' heel on this one

This is a great product in just about every regard. I use it for biking and when I'm on the road I absolutely love it. I then come home and upload my ride into Sports Tracks and it's great.But... when you first start out (or after a long break), it will take anywhere from 5 to 15 (yes, 15!) minutes to sync with the satellites. This unfortunately makes the 301 frustrating and often useless.When I'm riding to work I don't want to wait for this stupid thing to sync. When I'm on a long weekend ride my buddies don't want to sit around waiting either. This just makes the thing useless. I am now shopping for another GPS system that doesn't have this problem.