Exercise and Fitness

I.E., you can have the phone in standby and it still works in the background.

I have had no issues in a forest. I use it for mountain biking frequently in NC/GA where most trails are under a canopy.

Battery is pretty good. As a rule of thumb, it shaves about 30-40% off my battery life if I have it on and recording. I can get some of that back by turning off the cell coverage, wifi & bluetooth.

Some maps are free. You can download public maps and their own maps:

MotionX Road
MotionX Terrain
NoAA Marine

And you can use these maps, but they require a connection:

Bing
Apple
Google

Finally, you can buy a $5 upgrade that lets you pull down additional map sets. Examples include USGS BAsemap and Open Cycle Maps. Some of these other map sets have a charge, but most of them are free.