If you can run your entire function in V8 and don't need node, Cloudflare Workers is MUCH faster, more affordable, more manageable, and more reliable. They get cloned all over the world and you're not region-locked.
We've moved from AWS to Cloudflare and I can confirm Workers are awesome. The only downside is lots of work required to get npm packages running properly. Due to the lack of Node.js' runtime, bundling, shims and stubbing required to get stuff like "fs" and "net" compiling. AWS is more mature, has a better community support around it and generally the tooling is more stable. Workers are quickly catching up, though, with great new additions such as ES modules, custom builds, Miniflare, etc.