Webpack is easier to use. More boilerplates and plugins available to get started from.
We chose Vue because it was easier to get started using, especially for developers on our team that didn't already know React. Vuex is easier than Redux and that sealed the deal for us!
Python has a better Python SDK and it has less gotchas overall. For backend development, this was the choice that gave us the fastest velocity!
Modern JS is just better!
Typescript has more features and (it feels like) a better ecosystem. I used Flow when I've used fusion.js and I prefer Typescript. I also like C# though, so that could be an influencing decision!
We prefer Lambda for what we target due to faster startup times, longer max runtimes, and cheaper pricing.
We use Monaco for the editor and it's way better than Ace!
Intercom's live chat is killer. That's been amazing to have for us! Other analytics tools do much of the same stuff as Intercom so we've chosen to just use Intercom for now.
Redis is insanely fast. And the APIs are great. We use transactions a ton to keep state consistent across many servers. Never had any problems with Redis -- it is rock solid!
I actually love emacs and it's a great tool to have. I use Evil Mode in emacs though, because at the core I know that Vim will be on every server I ever SSH into. JetBrains IDEs have support for Vim bindings, trivially. And it just works very well across many environments!