It's OK for what it does: basic text editors for a page's HTML, CSS, and JavaScript, and a preview window. Each text editor has syntax coloring, autoindent, autocompletion (e.g. enter p tag and it produces closing tag).

But no smart search (the browser's Ctrl+F to seach for e.g. "10" will find line numbers 10, 100, 101, etc.), no search and replace, no keyboard shortcut for run, no ability to edit an existing web page. You can't save to particular locations and file names (a browser limitation).