Yeah, I've had issues with tree cover too. But honestly, even with syncing and all that, I still get weird readings sometimes. Like, I know I didn't run 10 miles in 30 minutes... I've just learned to take it with a grain of salt and focus on how I feel instead. Anyone else just use their watch as a rough guide and not stress too much about the exact numbers?
GPS watch is a must for me too. Still get lost sometimes, but at least I know how far off course I am.