Warranty and service vary from dealer to dealer, but generally most Centurion dealers are top notch from my experience. There are exceptions for sure, but generally speaking they do a superior job to what you get from your average Malibu dealership.
As far as QC goes, nobody is on par with Toyota in the marine industry and honestly, they can't be. The technology and engineering that Toyota can afford, along with production capacity will draw out patterns for issues that can be addressed more easily. It's the benefit of building hundreds of thousands of vehicles vs. hundreds of boats.
With that said, the QC that goes into Centurion, Supreme and Nautique is the best in the business. There is a reason a Centurion boat has a 8-10 day build time and a Malibu is 4-5. There are multiple steps in the process that Correct Craft does that are either minimalized by other manufacturers or omitted entirely. This accounts for a lot of issues that customers are seeing with boats that are being built by companies that are more accountable to their shareholders than their customers.