When I had an android smart phone, I downloaded BackCountry for topo maps. As far as field work, I liked it better than my Garmin. The screen is bigger, and the colors are more defined on the smart phone and it would actually plot tracks with the phone in my pocket. My Garmin doesn't do that. It was accurate enough for me, for most things, but not as accurate as the Garmin. The UI on the smart phone with BackCountry was infinitely easier to use than the Garmin (the touch screen helps). As a plus, you get to try the demo free for 30 days. I never really tested how it worked once I got home and on the computer.