Because WAI-ARIA is relatively new, its support across browsers and assistive technologies is still somewhat inconsistent. That should not, however, discourage you from using it. Be aware that workarounds may be needed in some cases, at least for the short term as browsers and assistive technologies progress to implement support for the full WAI-ARIA specification.
For now, it is advisable to test WAI-ARIA implementations across multiple browsers and screen readers.
Look over the following references and add them to your Toolkit.