Both Mauviel and Brooklyn Copper Cookware make high quality tin-lined heavy copper cookware. In addition, Mauviel makes other lines of SS-lined copper, clad, and induction cookware etc. They are a much larger company, and do not make everything by hand.
Brooklyn Copper Cookware is entirely made by hand, and they only make tin-lined heavy copper cookware. They have a smaller range of products, with more to come, and are more artisanal.
I don’t have identical pieces, but I do have a BCC 3QT sauté pan and a Mauviel M’tradition 11" rondeau. They are both over 3mm thick and are lined with tin. They both have lids, and so I have cooked similar dishes in both that involved browning and then braising meat. They both performed equally well. The Mauviel 11" rondeau has bronze handles with 2 rivets each (and not 3 as they once used), and has a hammered exterior. I imagine it was hammered by machine as it looks too perfect to have been done by hand (but I am just speculating). Both companies make high quality products that will last for generations, and will outlast us.
Comparing Mauviel and BCC would be like comparing a high quality off the rack suit (such as a Brioni) with a bespoke suit. Both will look good, but one will feel somewhat better and be more hand crafted.
I am happy to have both Mauviel and BCC in my collection.
