Free & open source
It's free of charge for everybody, for any purpose (including commercial). It's safe, as anyone can review source code.
Advanced SQL code editor
The SQL Editor window assists user with SQL syntax hints & highlighting, provides pretty-print code formatter, marks syntax errors. You can Ctrl+click on table mentioned in SQL query to open that table (or index, or trigger, or view).
Multiple databases seamlessly
You can execute SQL statements that refer to multiple databases within single query, thanks to transparent database attaching mechanism built into the SQL Editor of SQLiteStudio.
Custom SQL functions
Custom collation sequences
You can implement your own collation sequences (i.e. algorithms for comparing 2 values, that could be used in ORDER BY clause, etc).
SQL & DDL history
You need that query you executed 2 weeks ago? No problem. SQL Editor has a "History" tab. You need to upgrade production database the same way you did locally with SQLiteStudio? Use DDL History window - it has all DDL statements as executed by SQLiteStudio.
D&D between databases
You can Drag & Drop objects (tables, indexes, ...) between databases in order to copy or move them, with or without data.
Works on all 3 major platforms - Windows, MacOS X, Linux. Can be compiled from sources on other, less common platforms (like FreeBSD, ...).
There is a portable distribution. No need to install it. Just download the package, decompress and run. No administrator rights are required.
Do you need to test your application quickly with some pre-generated data? SQLiteStudio can populate tables for you with various strategies (constant, sequence, random number, random text, dictionary-based text, script code generated).
SQLiteStudio can import data from various formats (currently CSV or any text file using Regular Expression), or export to various formats (SQL statements, CSV, HTML, XML, PDF, JSON).
SQLiteStudio supports plugins of several categories. For example another scripting language can be added with plugin. Another import or export format, another table data populating strategy, another SQLite database format, SQL code formatter, code highlighter, table cell value representation renderer - all of these can be exteded with plugins.