I got this App after buying a different one that left me in the subway station looking crazy because I couldnt figure out where I was going.
This is by far the best subway App I have used. It lest you pick your starting and ending station by name, whats cloest on a map to a point youre goiing, or which one is cloest to you. Starting and tranfer stations have an accurate train schedule so you know how long your wait is. The GPS and Google Maps function is awesome because if you going sightseeing like I do you might end up far from your starting place. Just use the GPS and it will point you to the cloest station and from there it will get you to where you need to go.
I didnt use the Lite version but I would gladly have paid more for this one. This is the App youre looking for!
Diabolic21 about Seoul City Metro - Seoul, South Korean Subway Guide, v1.2