IDEA places an emphasis in safe refactoring, offering a [variety of features](https://www.jetbrains.com/idea/features/refactoring.html) to make this possible for a variety of languages. These features include safe delete, type migration and replacing method code duplicates.
Ranked in these QuestionsQuestion Ranking
Pro Still Vim but with upgraded features and some issues fixed
NeoVim was a complete rewrite of Vim, with new features added and underlying issues resolved thanks to the Vim code base. The keybindings and configuration are the same as Vim, so the switch can be pretty simple.
Pro Better integration with external tools
The core text editor is "headless", meaning it's detached from the user-interface so other programs can hook into it. This enables better integration with IDEs and browsers, where "Vim mode" has typically been a poor substitute because it was a partial rewrite or a partial port at best. One of the advantages of Vim has always been ubiquity and Neovim makes it even more ubiquitous.
Pro Powerful plugin model
Vim plugins have always been useful, but tied to specific languages. Neovim's architecture provides better separation between plugins and the core product, so that plugins are completely flexible and can be written in any language.
Pro Modern code base
As a refactor over Vim, Neovim has greatly improved its code base. For example, some functionality is handled by libuv, the same code base that powers Node.js.
Pro Built-in terminal emulator
This avoids the user having to make any installations.
Pro UI Agnostic
The core functionality is handled apart from the UI, meaning that Neovim can be embedded into any other GUI system, such as Atom.
Pro Async plugin execution
Pro Active development community
Pro Comes with some good configurations out of the box
Some typical configurations most of VIM users make are default in Neovim.
Pro Opens a 3Gig Text File in a few seconds
Not many editors can open such a large text file so quickly.
Pro Fast and light on memory usage
New neovim editor instance starts instantly and you can have multiple editors open at the same time, because id does not require a lot of memory to run.
Pro Work in TUI (Tex User Interface)
Neovim can work on terminal, on a remote server over ssh.
Pro Terminal mode is very convenient for testing code in a split window
Pro Smart refactorings
IDEA places an emphasis in safe refactoring, offering a variety of features to make this possible for a variety of languages.
These features include safe delete, type migration and replacing method code duplicates.
Pro Fast and smart contextual assistance
Uses a fast indexing technique to provide contextual hints (auto-completion, available object members, import suggestions).
On-the-fly code analysis to detect errors and propose refactorization.
Pro Lots of plugins
Many plugins are available for almost any task a developer may need to cover. Plugins are developed by Jetbrains themselves or by 3rd parties through the SDK available for writing them.
Pro Stable and robust
IntelliJ IDEA hardly ever crashes or has any issues that plague other Java IDEs like file corruption or slowness.
Pro Android support, JavaEE support, etc
A very complete development environment support.
Pro Support for many languages
IntelliJ supports many languages besides Java, some of these are: golang, Scala, Clojure, Groovy, Bash, etc.
Pro Intuitive and slick UI
IDEA has a clean, intuitive interface with some customization available (such as the Darcula theme).
Pro Clear and detailed documentation
The documentation is exhaustive, easy to navigate, and clearly worded.
Pro Free version available
There is a free community edition (open source) and an ultimate edition, which you can compare here.
The ultimate edition is available for free for one year for students but must be registered through an .edu e-mail account.
Pro Many convenient features
These simplify the daily work, e.g. copy/cut a whole line without the need to select it.
Pro Very powerful debugger
With ability to step into a certain part of a large method invocation (Shift+F7), drop frame, executing code snippets, showing method return values, etc.
Pro Gradle support
Pro Buit-in Git support
Con Limited cross platform support
Neovim is not available for many legacy platforms
Con Ambiguity in extensive documentation
Con No graphical editor yet
At the time of writing this, no equivalents to gVim exist.
Con No stable release yet
As of yet, Neovim is in an unstable point in it's development. There is no stable release and using it for the moment should be done with caution as many features may change in the future.
Con Poor feature discoverability
Con Poor support for external tooling
Con Requires Brain Mode Switching
When editing in vim, you have you use the vim keys; when editing in every other window on your PC, or in Word or Excel or other application, you need to use the standard system key combinations. Learning the vim combinations can actually make you SLOWER at everything else.
Con Consume brain energy for editing that should be used for logic
Text editing in vim can be great once you've learned it, but it requires thinking about combination of commands. In other editors, you don't have to think about how to delete this part of code. You just think about how to implement a feature, what is a good design for this code. Even after you get used to using vim, it still requires your brain for editing.
Con Modal editing
Has a split between editing text (Insert Mode) and the other functions of the editor. This can distract you from thinking about what you're trying to accomplish.
Con Split the VIM community
Con High effort to customize
A lot of time and effort is put in to make it specific to your needs.
Con Slow startup
Startup can be slow deepending on system configuration
Con Uses a lot of RAM
Con Standard hotkeys behave differently
Seems like hotkeys assignment in Idea has no logical consistency.
Like «F3» is usually next match, «Ctrl+W» - close tab, etc — they map to some different action by default.
There is a good effort in making the IDE friendly for immigrants from other products: there are options to use hotkeys from Eclipse, and even emacs. But these mappings are very incomplete. And help pages do not take this remapping into account, rather mentioning the standard hotkeys.
So, people coming from other IDEs/editors are doomed to using mouse and context menus (which are rather big and complex).
Con Bugs are not solved as often as they should
They are more interested in adding new features or issuing new versions than solving bugs.
Con Cannot open multiple projects in the same window
Con Built with closed source components
The version with full features is not opensource. Parts of the code are under apache licence though.
Con Lack of plugins
IntelliJ supports a very small amount of plugins. Although these are 'quality approved', many features are missing and can't be implemented because of that.