RE: cubs make good trainers??
Seems to me a couple of generations of rider scale pilots learned to fly in Cubs.
One of the things I went through, and I've since seen many other fledgling modelers go through, is having to learn what the rudder does after solo.
My original instructor only used the rudder for aerobatics, and complained that my Goldberg trainer didn't have enough aileron authority, although it was set up by the book.
I learned the hard way (several different kits) that novices need to master the rudder before they get the model in the air, not after they're trying to land in a cross wind.
I think a tail dragger is an ideal primary trainer because the student will have to learn the proper (and continuous) use of the rudder if they want to get the beast off the runway
(other than in the grass, that is).
Yes, a Cub makes a fine trainer. It is not as easy as trike gear, and you will spend a bit more time learning what the rudder really does than someone with an ARF .40 trike trainer, but you'll be a better pilot when you solo.
BTW - you may already be infected. Not wanting just another .40 ARF trainer may mean you'll be buying balsa in bulk, building pull-pull systems, and worrying about the right FS number for your newest Big Iron before you know it.
Welcome to the nuttiest hobby in the world.