SciTE vs TextMate

It's property files allow for fine tweaks of its behavior, at a global or per language / project level. These textual settings might be confusing for those used to preference dialogs, but prove to be powerful, flexible, and fine grained.

With less than 2 MB of binary on Windows, SciTE starts instantly. Plus, if you don't need all the config, syntax files, blah, there's a 678k standalone .exe version. Nothing is going to beat that for lightweight and start-up times. Stick it in a folder that is already on your PATH.

Based on the Scintilla source code editor, SciTE has some advanced features like rectangular editing, simple regular expression search and replace, code folding, etc. It allows the user to launch a compiler or interpreter, and it can also interpret the error messages, jumping at the location they point to.

Lua scripting is key to SciTE's power and flexibility. The Lua scripting language can be used to perform complex text transformations. It's relatively simple syntax and its large user-base makes it a great choice for a scripting feature.

The console window can show the result of ran commands (like build current file, reporting warnings, and errors), but also accept interactive shell commands.

SciTE works on Windows and Linux, and it also has a commercial port on MacOS.

Lexers providing folding and syntax highlighting are based on code, not on regular expressions. They support context, nesting, special rules, etc.

SciTE is written in C++, with lot of contributors, both to the core and to the numerous lexers.

Has a simple graphical user interface

Textmate is open source and hosted on GitHub.

TextMate has an extensive library of plugins which can be further extended to make it even more powerful.

It's lightweight footprint makes it extremely fast to load and use.