The Spicy Chicken Filet Burger at McDonald's Taiwan is a variant of your standard McChicken but adapted for Taiwanese tastes. It is also sold by McDonald's China. It's also about twice the price of a McChicken at approximately $2.
Unlike the McChicken here in the States, some McChickens abroad have the same toasted sesame bun you find on a Big Mac, but the same mayo and shredded lettuce. The presence of sesame seeds doesn't make a whit of difference to me though.
The real difference between a McChicken and the Spicy Chicken Filet Burger, and where the dollar difference comes in, is the chicken patty.
The chicken patty in the Spicy Chicken Filet Burger is cut from chicken
In sum, the chicken was juicy, the breading was crunchy, and the lettuce was crisp. I enjoyed it very much.