We're using IronWorker and Lambda for a current project. Our (Go) code can run on either and we've designed the app to easily swap out the backend in case of service failure.

Pros of IronWorker: More language support, better logging, easier to debug, scheduled tasks via API (this is the main thing stopping us going all in on Lambda).

Cons: Slower start up time (~2-3s on average compared to milliseconds with Lambda), pay upfront rather than pay for what you use, no choice re. CPU/RAM.