When comparing Textastic vs Suplemon, the Slant community recommends Textastic for most people. In the question“What are the best programming text editors?” Textastic is ranked 45th while Suplemon is ranked 51st.
Specs
Ranked in these QuestionsQuestion Ranking
Pros
Pro iOS version available
Pro Supports 80 source code and markup languages
Textastic has support for several script and markup languages.
Pro Very fast
There's no need for hundreds of modules to be loaded on every start of Textastic. It's perfect for the fast editing of files.
Pro Supports online sync
Textastic can sync with iCloud documents.
Pro Code completion
Pro Native multi cursor editing on the command line
Multiple cursors & column selection allow versatile ways of editing.
Pro Low learning curve
Does not drown you in keyboard shortcuts or non-intuitive use-concepts as you start using it, but high-level functionality can still be easily accessed when the need for it arises.
Pro Mouse support
Scroll wheel works automatically. With mouse mode (F8) the cursor can be moved with a left-click to a desired position, and new cursors can be added with right clicks.
Pro No required dependencies
Pro Shows linting messages for Python code (requires flake8)
Cons
Con Mac only
Textastic is for Mac only.
Con Proprietary
Textastic is a proprietary software and needs a license which costs $7.99.
Con No region selection
Some selection features that are taken for granted in other editors are missing here. As they say in their documentation, if you want to copy and paste part of a line, you need to use the mouse to select it and copy with Ctrl + Shift + C.