I like both. However, with apples, one has many more choices and they last longer.
Bananas. My mother makes a "dessert" of yogurt, bananas, blackberries, strawberries, chia seeds, hemp seeds and flavoring. It's good. I don't think you can use apples the same way but she does make a great Tu B'Shevat salad with shredded apples.
Ok, after all this thinking out loud, I'm going to go with bananas. There. Whew. That was a tough one lol
Love them both. I do eat an apple every day!