I need to investigate a little more about ajaxexplorer. It is a really complete program very usefull for file management and database management (among others).
Here you can read his features (just a few lines)
It can be configured to be used just as a simple ftp web client if someone wants (as I posted), but with a few changes it can be integrated with ispconfig.
It is very easy to use, visually it is lot better than net2ftp, and... as ftp, it allows drag and drop from desktop, preview of files (images included), direct file editing with indented code (very usefull for php code editing without file downloading).
I recommend you to test it.