I didn't learn on either... they weren't DESIGNED yet. [X(]

I have given lessons to a bunch of beginners using each. They are both decent, relatively inexpensive trainers. If I had to chose one over the other, Id get the PT-4 and I'd get the kit of either in preference to the ARF versions. (but I like to build... )

I think the PT-40 ARF is just a bit more rugged than the Tower ARF. Not a lot... but enough. The Avistar... is in between on ruggedness, a little superior on aerobatic ability, not quite as stable. (but you always trade stability for aerobatic ability) All 3 are GOOD!

Its kind of like comparing a red Chevy to a white one to a brown one... All the same model, all the same year, one has the power windows (others manual), one has auto transmssion (others manual), one has the CD player. There's not MUCH difference, but you can find it.