Step Debugger for PHP other than Zend Debugger

I just wanted to see if anyone is aware of any other debuggers capable of stepping through code.

I am aware of xdebug and use it as well as Zend Debugger and other debugging scripts (i've written my own widgets for this already).

However I am looking for a good replacement for step debugging - I've searched and searched but have yet to find anything. Is there anything else out there that can handle this? Surely Zend Debugger isn't our only solution?

From stackoverflow

• I use php_dbg for my PHP step-debugging (comes with PhpED).

  Syntax : Awesome - I had heard of PhpED but wasn't aware of this. I'm going to give this a go and see if it fits the bill. Thanks!