Definitely buddy box. I've had self teaching attempts with 3 channel planes with no success, helis on a sim and self taught with mild success (lots of crashes and broken parts though), and finally planes on a buddy box with great success and no "crashes" (a few hard landings and deadsticks with no to mild damage [props and landing gear blocks]). You learn the CORRECT way to fly when using an instructor without picking up the bad habbits during training (those can still come after solo). After soloing, I got overconfident (read: cocky), and started doing things out of my skill level at 2-3 mistakes high. I've had a few way too close calls doing that (I could already hear the crunch coming), but was able to save it because of my altitude. Lesson there: just because you can fly, doesn't mean you can do just about anything that you can on the simulator. Even after solo, there's still a LOT more room for improvement/refinement in flying skills.

The best way to go: Get a simulator to get familiar with the controls and orientation, then get with an instructor, continue re-enforcing what the instructor taught by practicing on the sim away from the field, solo, continue to refine your skills (never stop doing this, as well as simulator time, as sim time will help keep your thumbs working and assist in learning the inputs for new maneuvers), work on approaches and landings from both directions, then gradually push your limits at 3+ mistakes high to learn more maneuvers, using a sim as you go.

Key points:
1. Simulator (Familiarization)
2. Instructor
3. Simulator (Re-enforcement)
4. Practice
5. Simulator (Refinement)
6. Take it slow
7. Practice
8. Simulator (Moving on up)