api gateway: centralized vs decentralized

So, I've been thinking a lot about API Gateway patterns lately. We're seeing more and more services pop up, and the question of where the gateway logic should live is becoming a big deal. Do you lean towards one big, centralized API Gateway that handles all the routing and those cross-cutting concerns, or do you prefer a more spread-out approach where each service, or maybe a small group of services, gets its own gateway? What have you guys found are the trade-offs with each? I'm really looking for some real-world war stories here!