Helix. Instant startup. Minimal configuration required. Has all of the killer features I want from an IDE anyway.
EDIT: I assumed people would just research this anyway, but a more complete list of features I enjoy from Helix:
- very responsive
- modal editing
- declarative configuration file format (TOML, not Lua)
- language server protocol
- debug adapter protocol
- written in Rust so I am more likely to be able to submit a PR if I need to
Some cons (all known issues on github):
- no plugin API yet
- inline LSP diagnostics are overly intrusive and can overlap your code
- cold-starts the LSP when you start the editor, so you might need to wait for symbol queries in a large project