Spacemacs

The most full-featured and innovative Emacs distribution.

Spacemacs abstracts related Emacs packages/configurations through its set of layers (and there's a lot of layers, a lot). Example: you want to write Java code, then you just add "Java" to your ".spacemacs", restart Emacs, and you're mostly done (I say mostly because sometimes you'd want specific stuff like LSP and you'd need to set one or two variables and/or install the respective package for your distribution, although Spacemacs also offer the option to install it for you). If you want something that isn't already provided by the existing layers, you can 1. easily install specific Emacs packages and tweak them to your liking; or 2. create your own layer.

• It offers Evil-mode integration (you don't need to use it though).
• It has great documentation (both Spacemacs in general and for every layer), which you can read either on their very good website or inside Emacs/Spacemacs.
• Its leader key ("space" on Evil mode, and "M-m" on Emacs mode) and mnemonics are so well thought that's no surprise it has inspired a lot other projects like Doom Emacs, Spacevim, Space VS Code, and so on.
• It has this "transient state" for some specific modes which is another level of mode/keybinding abstraction, which is great.
• Project management through its "layouts" (and then "workspaces" IIRC) is very good.
• There are so many great things about Spacemacs it's hard to list them.

But it has it cons too:

• Performance is not great, mainly and obviously when you add too much layers and customize it too much.
• May crash/freeze a lot.
• Development currently is in a state of Anarchy, as its main maintainer and creator just stopped maintaining it. Development still very active though on the "develop" branch by users and people who have admin permissions to that branch.
• Community is not so supportive when you have specific issues that may not be related to Spacemacs but Emacs in general.
• When you have issues it may not be an easy of a task to debug because Spacemacs abstraction is relatively complex.