XDebug or Zend Debugger?
It seems to me that they have both the same function set, but I'm not sure.
What are the differences in functionality between the two?
Solution 1:
Zend debugger is only available in binary format, so you need to be careful to download the right version to match your version of php ( http://downloads.zend.com/pdt/server-debugger/ ). I was able to get it working with Eclipse PDT and do line-by-line debugging with a local XAMPP installation. I think Zend has some additional features, but in my experience it has been easier to set up.
XDebug is much more open, but I haven't successfully configured it to work with Eclipse PDT.
Solution 2:
XDebug works with Eclipse and with Netbeans (and some other ide's).
ZendDebug doesn't work with Netbeans. ZendDebug is already configured in ZendServer.