How far you can see depend on various conditions, but the Phantom is small and white and disappears fairly quickly against a bright sky. The radar is very helpful. Touch the icon and it expands to show more detail. Touch the detail view and it toggles back to the smaller version. I found it's the only way to tell where you're at and what direction you're headed.
The other thing to remember is the wide angle lens makes everything look farther away than it really is.....don't fly too close to things you see in the video stream on your mobile device until you get a good gauge of actual distance.
