I bought these after reading a lot of reviews and to see the bundle was a great add. 
and since having used them they live up to the hype so far, i am a cast iron loyalist but am now using these as well.  I will only add that the card board ring in between the two pans for packaging and shipping - storage, left a ring at the bottom of the big pan. i washed it well but did not want to scrub it off so you can see a bit of the residue from the cardboard.
i have not seen a difference or tasted any thing odd from the issue though. Be careful with the handle as user error if you hold the or grab the handle too close to the pan and touch the metel between the grip and the pan it is very hot,  that is my mistake.