When comparing Toad vs HeidiSQL, the Slant community recommends HeidiSQL for most people. In the question“What are the best MySQL client applications for Windows?” HeidiSQL is ranked 1st while Toad is ranked 8th. The most important reason people chose HeidiSQL is:
Licensed under GNU GPL.
Specs
Ranked in these QuestionsQuestion Ranking
Pros
Pro Reliable
Toad is maintained by Dell and has great community support.
Pro Free
Toad is free to use.
Pro Free
Licensed under GNU GPL.
Pro Portable
Alongside the possibility of downloading the installer and sourcecode, a portable version of the software is available.
Pro Great UI and ease of use
HeidiSQL has a comprehensive and intuitive interface.
Pro Syntax completion

Pro Lightweight
Pro Great user management
The user manager of HeidiSQL can easily set privileges on a per-database level or give access to only certain commands.
Pro Data synchronization
HeidiSQL can compare and synchronize your data and structure between local and remote databases.
Pro SSH tunnel
HeidiSQL allows connecting to your MySQL database via SSH tunnel.
Pro Connect to servers via command line
You can use command line parameters to automate connections.
Pro Works fine with Wine under Linux
Cons
Con Fewer features
Still some more features are required to add. Other than that its perfectly fine.
Con No built-in SSH tunneling
Toad currently doesn't provide built-in SSH tunneling.
Con Can be buggy
HeidiSQL is known to have some bugs that results in crashes.
Con Intellisense is not intelligent
No intellisense for columns unless table name is aliased.
Con UI design is very bad
Generic windows form
Con No session backup
You cannot recover your session after close or even worse crash.
Con Works under Linux only with Wine
It works quite well under Wine with Linux, but you must always take notice if the last version of HeidiSQL has been tested, for it may not run at all. There are some bugs in the Wine version that can be annoying and you have to kill the program and restart it. A native Linux version would be great.
Con No built-in debugger included
