[link=http://www.spadtothebone.com/]SPAD[/link] are awsome! I am learning to fly using a plane I built from scratch based on the SRR. It's a bit heavy for it's wing size but it flies In my opinion there are three huge advantages a SPAD trainer has over a balso trainer:

1. Very resilient or almost indestructable
2. Very fast to build
3. Very inexpensive, as already mentioned, $45 gives you enough material for three planes.

In my opinion this is the way to learn! Just to give you an idea of the durability, my friends trainers aileron fluttered and locked up the servo. The plane literally screwed itself into the ground. The nose of the plane was buried a few inches in the field. Apart from a dirty engine and a small crack in the wing foil everything was well with the plane.