I am looking for a hot backup system for mysql databases? I like to ask you for experiences and expertise.
I use the MySQL GUI Administrator Tool. It has a backup tool, which you can use to schedule daily backups through windows. You can create different backup projects, schedule the backups, and control how the backup runs and the type of output file it creates.
I've always found it reliable, and the other tools bundled with it are also useful for basic database administration.
So the place you want to look for good solutions to MySQL issues is Mysql Performance Blog/Percona. Specifically, what you want to do is use their XtraBackup, which fixes a number of issues that occur with InnoDBs hot backup. You'd be well served to use their patched server with their InnoDB replacement XtraDB.
They integrate a number of third party patches for MySQL, including their own and Google's, and have enhanced the InnoDB storage engine with fixes, enhancements and better logging. Additionally, Percona sponsors a fantastic toolbox for MySQL called Maatkit, which gives some components to help you with backups and integrity checks.