That's really a personal decision. Some people can think of many other things they might spend money on other than fast food. Some people really enjoy fast food and they might chose to spend their money on that. For some people, too much chic-fil-a or other fast food might mean a serious weight gain. For them, I would say no it isn't worth it. However, some might decide they want to exercise more so they can enjoy those extra calories. It really is a personal decision and not something we can objectively judge from the outside.
The last two towns I've lived in have not had a free-standing store; the only way to get Chick-fil-a was to go into the food court of the local mall. Because of that (and because I'm not a real mall shopper), I have always thought of it as a treat. It's not cheap, but it is good food in a family-friendly environment. I like that the menu is fairly limited, as well--not as many decisions for me to make. It is also inspiring to me that every Chick-fil-a store is closed on Sundays because they want their employees to be free to attend church and spend time with their families; agree or disagree with that, but they actually practice what they say they believe. I like that.
My husband and I have this conversation about twice a year, which how often we find ourselves at Chick-fil-A. As far as food goes, no, I don't believe it is "worth" the high "fast food" price. That said, Chick-fil-A is the most pleasant fast food environment I've ever experienced.
Their customer service is outstanding. They go out of their way to take care of children (a huge plus for us). The restaurant is beyond clean. They think of so many things that no one else thinks of (bibs, sani-wipes in the kids' area, cups of cheerios in the morning while you wait for your food with little ones, Tuesday night art night). So in this regard, I still claim to love Chick-fil-A and when we are desperate for a night off of cooking, we'll still hit it up once or twice a year.
(I do remember we had it in our student union building in college and so I could pay for it with my meal plan money. Then, it always seemed worth it. Funny how my perspective has changed.)
In evaluating your choice of fast-food restaurants, why not compare calories and grams of fat and carbohydrates to see who has the better food value? Despite this consciousness, however, we all have a taste preference and/or a weakness for a certain place.
One thing about McDonald's: In my family's experience, when traveling by car and in need of a fast meal, the McDonald's are more consistent in the quality of their product (i.e. freshness of bread, texture, taste) nationwide than other major chains.
The answer to your question depends upon your priorities. If cost is the most important factor in your decision-making process, no - you could find a meal for less cost. If nutrition is of prime importance, you could compare calories, fat, sodium, and other contents between a Chick-fil-A sandwich and other possible fast food sandwiches to determine which is the healthiest. If taste is the biggest consideration, you would need to try a Chick-fil-A sandwich and some other possible choices; then you could decide for yourself which you felt tasted best.
The only bad thing about Chick-Fil-A is that they aren't open seven days a week. Their chicken biscuits are amazing, and their sandwiches and nuggets are as good as it gets. In addition, their waffle fries are the perfect combination to everything else on their menu. YUM!
I certainly like their sandwiches more than the barely edible burgers at McDonalds and other fast food chains. Price-wise, Chick Fil A is a bit more expensive, but I consider their chicken sandwiches a healthier and better-tasting alternative to the Big Mac.