I agree there are some that are marketed as good trainers but fly like a rock. I think the aerodynamic platform for any trainer is pretty much the same. But I taught a person to fly with a G.P. slow poke .40. while this plane is considered a sport model it served its purpose as a trainer. Of course there is a catch. This guy picked it up fast, and in my opinion will probably excel to be a better pilot then me. he hasn't crashed it yet and was doing loops and rolls and flying inverted close to the deck by the end of this season. he soloed in march and flew about 3 times a month. Take the balsa USA stick .40 now there is one ugly plane. I mean ugly. But it is a trainer and falls into the category as being stable, slow, easy to see, light wing loading, and tough.Then there once was the flightcraft ARF trainers nice looking, a little less stable, heavy,came in fast, not durable. In my opinion it did not make a good trainer. didn't have the quality's. So to say all trainers are the same is to discuss what a manufacture markets as a trainer. But if you put numbers on the aerodynamic platform of a Good trainer then yes any manufactured plane that fell within a given perimeter would be the same. who would have these numbers. well if you did a poll on what is the best trainer and averaged the weight, wingspan length, wing loading, dihedral etc you would probably find the magic numbers that you could compare every other trainer with. so given this, to an experienced pilot one would not suggest a trainer to a newbie that falls short of the proper characteristics of a trainer.