If I may without sounding disprespectful, I'd like to retell your story from the perspective of a former beginner who is a trainer now.

First, you bought a completely inappropriate plane and didn't get any help flying it. Predictably, you broke it, and the hobby shop was right to tell you that a new fuselage was the best fix given your lack or repair skills at the time. Then you bought a more appropriate beginner plane, but still didn't get any help, and still didn't learn to fly successfully. You also didn't have the financial resources to keep your equipment in good shape or get the right stuff. I don't mean to say any of this was totally your fault, but it certainly wasn't anyone else's either, right?
Then you asked for help- good move. You listened to the instructors and bought an appropriate beginner airplane. You also put time into the hobby, coming to events and taking a class- good move again. But then you got upset when volunteers couldn't work around your schedule and you didn't take the time to learn how to set up and take care of your equipment, hence reliability problems. One instructor went out of his way to help you, but you didn't like him and didn't take advantage of his interest in you. You then lost interest in learning to fly nitro trainers because it wasn't easy enough or fast enough.

I say all of that to help you understand that this hobby requires comittment. A few guys get it in a week or two, but most don't. You have to be comitted to meet with instructors when they can meet with you, and you have to be comitted to maintain your equipment properly. You also have to be able to spend the money that the equipment and club dues require. For most high schoolers, 6 months is an eternity to stick with something. In this hobby, 6 months is enough time to be a good enough pilot where the others aren't afraid to be in the air at the same time as you. If you will make the comittment to work at the hobby and learn it, the reward is building skill in RC flight that lets you take an object that you built or at least set up, and make it do exactly what you want it to. This is real flying in miniature, and there is a great satisfaction in learning to do it well.

To answer your questions about airplanes- anything that is easy and fast to get in the air is going to be low performance. Stick with the nitro trainer and get the instruction you need. Listen to the guys who are willing to help you and show them that you apprciate whatever they do for you. Then work at flying until you are as good as they are.