There are more than one version of Inspect.exe. The latest to my knowledge is the one dated from 2012 that says version 7.2.0.0 in the help/about dialog box.

The old one doesn't have a tree view on the left with all detected automation elements displayed in a tree, so it's easy to check you're using the right one.

The latest one works quite correctly, however, IMHO, the best tool so far to work with UI Automation is Visual UI Automation Verify. It's a .NET program, and he source is available here: UI Automation Verify (UIA Verify) Test Automation Framework.

Note that although it's a .NET program, it doesn't use the standard .NET automation dlls (more on that here: What's the difference of UISpy.exe and Inspect.exe? (From Microsoft Windows SDK)).

About the AutomationId property, to clarify my initial comment to the question, I meant its usefulness depends on the program that you're trying to automate.

If you own it as a developer, it's clearly interesting. For example, if you're working with WPF, you can use the x:Uid property, it's clearly meant for UI automation. In the Winforms space, it's also quite useful because UI Automation will use the control's AccessibleName by default and revert to the Name as a fallback, for the AutomationId value.

But there are many apps that don't rely on .NET (browsers, native apps, etc.) Usually, for these apps, it's easier to use other properties.