A properly designed rudder-only plane will roll and turn just as well as an aileron plane. You won't even be able to tell the difference.

As far as using the Beaver as a first plane, it'll work, but the Slow Stick is far superior for the first-time flier with no expert help. The Beaver has the same wing as the Pico Cub, but weighs twice as much. This translates into a faster airplane that is less forgiving and more prone to damage in crashes. On the other hand, the Slow Stick has a huge kite of a wing, and takes the abuse better.

On the subject of foam being superior to balsa, it isn't. Foam is simply different; it has its pluses and its minuses. The main reason today's "foamie" airplanes seem more resilient is because you're comparing apples to oranges. On one hand, you remember way back when, seeing large, fast, and heavy balsa airplanes turn into matchsticks when they crash. Here, you have the latest, lightest technology in tiny airplanes that fly at a walking pace. Make a foamie plane that's large, fast, and heavy, and it will look like Christmas in July when it crashes...