My 12 year old loved them and ate them every day of our most recent trip, but she's also gluten free and used to gluten free flavours. My 9 year old, not so much but she's also not so used to the gluten free flavours other than the ones I do at home which I season to their preferences. DH and I tried them and thought they tasted good. They do definitely taste like premade tenders rather than fresh but that's ok at a fast food location IMO.
Something that surprised me is that they came out differently at different places. I think some places may bake while others deep fry, or maybe they're just fried longer at some places. They definitey had a different colouring and seemed greasier (to my daughter's delight) when we ate at POR instead of POFQ one evening (we stayed at POFQ so mostly ate there). They're the same tenders that are served at the parks.
We always use a dining plan so I don't know which places might charge a premium and which don't. It is definitely possible to be charged more if you're not on a dining plan as pointed out by livndisney so be prepared for this.
I never think about how much longer it takes because we always have to wait longer for any allergy food no matter what we order so they don't seem any longer than any of our other allergy food. All food specially prepared for somebody with allergies will take longer so you want to prepare for that in your daily plans.