It provides same feature as in Visual studio for .NET development means you can put a breakpoint and see value of variable. The Watch window is also available.
You can also put conditional breakpoint as in VS 2008.
One more good thing that you can do it offline means no need to start VS.
Shortcut Keys for Debugging:
• Continue (F8) : allow you to resume the script execution once it has been stopped via breakpoint
• Step Over (F10) : allow you to step over the function call.
• Step Into (F11) : allow you to step into the body of the another function.
• Step Out : allow you to resume the script execution and will stop at next breakpoint.
It really increases the productivity and saves a lot of time.
Click Here to see in detail.