I decided not to renew. Even though it's essentially fee-negative with an AU, it's also a pain in the ... to do 10 separate $50 United gift registry transactions. Especially since they don't always get reimbursed, so I end up putting extra into the registry.
Still, the biggest dealbreaker for me is that I have no confidence that CNB won't change the benefits. When I applied for the card, it earned 3x at grocery stores, included a free CLEAR membership, and reimbursed seat upgrade fees. In the first six months, those benefits all went away. I don't want to pay $400 now only to find out that gift registry transactions no longer get reimbursed. I still think it's a great card, but I'd rather not tie up cash I have now in the annual fee, especially since I have other cards with similar benefits.
Last thing - I asked about converting it to a no-fee CNB card, and the agent didn't know if that's possible or not. She's supposed to call me back after researching it.