Does anyone have experience with the cheap (less than $100) 4-channel RTFs being sold on e-bay? There's a Mustang, a Zero, a Spitfire, a T-34 Trainer, and a Pitts Bi-plane. They look like they all come from the same factory (probably in China) and appear to have the Art-Tech transmitter. From personnal experience with the Cessna I know that the Art-Tech electronics are not very good, but if the rest of the plane is decent, it might be worth buying and replacing the receiver. Any comments?