Instances take longer to start up; Lambda processes requests in milliseconds or less. Lambda automatically manages a pool for you.
If you're running a predictable process and you know how long it'll take in advance, an instance may make sense. If you're running an unpredictable process, where you won't know how long it'll take until it's done, and it might be quite fast, the low startup time and fine-granularity billing helps.
If you're running a predictable process and you know how long it'll take in advance, an instance may make sense. If you're running an unpredictable process, where you won't know how long it'll take until it's done, and it might be quite fast, the low startup time and fine-granularity billing helps.