The Aerobird is an electric and more of a park flyer than a real glow trainer. As such, the glow trainer will be faster and much heavier than the electric and will display different flying characteristics. You are much better off getting a good glow trainer and, if possible, get together with an instructor on the buddy box. That will save you lots of heart break and a lot of broken planes.

I trained on the NexSTAR Select which is an RTF (Ready To Fly) comes complete, engine, radio, a CD for putting the thing together (will/should take you about an hour) and, what is nice, the RealFlight simulator that uses the NexSTAR aircraft in the simulator. Great to practice on before you head out to the field. It also has the Automatic Flight Stabalizer built in to the Futaba receiver. This helps you when you lose orientation by putting the plane back on the straight and level as soon as you let go of the sticks. Other things it has is the wing tip spoilers that help with tip stall at slow speeds, and the speed brakes/flaps... both are removable.

One main reason for having an instructor handy is especially necessary for the first flight, or at least someone with a good deal of experience to go over the plane to make sure it is truly ready to fly (controls set up right, aileron right is truly right (easy to mix up), the throttle works right, elevator is centered, and so on. Then have someone take it up for the first time to get the trim right so it flys straight and level with hands off the control sticks. At least that will give you a fighting chance of success if you are unable to get an instructor... but try hard to get one.. will make you a much happier flyer.

Best of luck no matter what you choose.. but I would definitely go with the trainer for now, get the Mustang later on after you have had a couple hundred flights with the trainer.