What do you mean by this? Like folded comments?
>debugger
So, gdb?
>unit tests
You can write unit tests in vim. You can also run them, obviously.
>refactoring
Again, what do you mean? Now it feels like you are just listing stuff or maybe I just don't know what refactoring actually means.
>file browser/project support
Granted the build in file explorer is pretty stupid, but the standard `:find` works perfectly well, so as long as you are not just randomly browsing, I don't see an issue.
>find usages/jump to definition
Vim has support for tags. I use jumping between them every day.
>full project intelligent search
What is this? Just grepping for stuff on whole repo or something more interesting?
>Even where vim supports these, it’s support is far weaker, less reliable
Only if you haven't used the features before. I definitely do not buy the "far weaker and less reliable" part.
>much more painful to set up than IDE support.
I am not arguing that vim does not have a higher learning curve than your average GUI editor/IDE, but are you seriously suggesting that you have not configured a single thing in your IDE? If you have, then your point is moot. I consider my .vimrc complex, but it has been build from scratch over the years as I've wanted more functionality.
>Among devs serious about productivity, it’s hard to imagine choosing vim.
Meh, sure depends on what you are doing. I rather have a tool which I can adapt to my needs than having to hunt down new tool for every project/language.
You ready for that killer feature that your IDE doesn't have? Try being productive on another machine. Over an SSH.
EDIT: I just noticed that I completely dismissed the "intellisense". Completion is build in by default. I can't remember if member list is, I use some tiny script that formats them all nice and neat.