Is ClearJel perceptibly superior to regular cornstarch when canning pie fillings?

This link might help with your question. It seems like if you don't want to use clear jel, that it is better to can pie filling without cornstarch at all. When you go to make the pie, cook down your filling with cornstarch before adding it to your shell.

http://www.sbcanning.com/2011/08/canning-pie-filling-education-in-clear.html

Clear jel is used when you cook something twice, first when you can it then when you cook it again to make a pie or turnover or etc. I use clear jel to make my canned apple pie filling so it won't break down when I use it in a pie later.

I use instant tapioca in my fruit pies. It doesn't break down in acidic fillings, when frozen or under high heat. And it adds the shine.

Here's what the USDA has to say about home-canning pie filling:

“Clear Jel®” is a chemically modified corn starch that produces excellent sauce consistency even after fillings are canned and baked. Other available starches break down when used in these pie fillings, causing a runny sauce consistency."

More here:

http://nchfp.uga.edu/publications/usda/GUIDE%202%20Home%20Can.pdf

Make sure you purchase the regular and not the instant version.

I believe that ClearJel is pectin based. Cornstarch on the other hand has the potential of overcooking (what happens to some custards when they get boiled past a certain point or reheated) and weeping or breaking the created bond of liquids.Since you will be rpocessing additionally in water bath, you may need to keep that in mind when you decide on your recipe's implementation. Additionally cornstarch will impart some cloudiness/opacity as well.

I have used cornstarch for years without an off taste. You just need to make sure you mix it completely

Cornstarch can impart a rather distinctive flavor, and not in a good way. And it has a tendency to get watery, if that makes any sense.

No personal experience but this may be of help:

http://www.foodsafety.wisc.edu/assets/pdf_Files/using_clear_jel_03.pdf