I started with SAM but eventually moved to serverless framework (serverless.com). Severless was made to be cloud agnostic so I didn't want that overhead.

But it turns out that serverless has more support (if you're googling for how to do things, you get more hits from serverless) and more developer friendly.

On of the best features is deploying just the code changes. This speeds up development time as a just code deployment is around ~3 seconds vs ~30 seconds for deploying the whole resource.