I voted for the World Models Sky Raider Mach I. It's very straightforward to assemble and comes with high quality hardware. The Nexstar ARF would be similar in these respects, but the big difference is wing design. The Nexstar wing is very large and it tends to "balloon" into upwind turns, making it difficult for new student pilots to control when wind conditions are above 10mph or so. The World Models Sky Raider Mach I, on the other hand, has a semisymmetrical airfoil with less dihedral. It will fly good in calm conditions, but will be more easily controlled in windy conditions. It will also perform aerobatics better after you're comfortable with basic flight and you want to learn how to fly inverted, do Cuban Eights, and practice Immelmann and Split-S turns.

I learned to fly on a Nexstar, and I liked the plane, but when the wind was howling here in Nebraska I was envious of the Avistar pilots.

P.S. - for everybody who suggested Sig ARFs and Kits, please provide contact information for Sig's Australian distribution office so brumbie flyer can contact them... [/waits for response while listening to crickets chirp]