While JAWS will announce all of the items in the list as results are first read, it only says "Blank" as you arrow through the available options. Tabbing out of the control and back in, also does not read the selected content.
This is basically the opposite of what happens when ARIA support is turned off.
In that case, there is no announcement when results come back, but JAWS will read each individual item as you arrow through the available choices. Tabbing out of the control and back in still does not cause JAWS to read the selected item.
This makes it seem like the ARIA version of the autocomplete box is missing either the appropriate ARIA roles or some other piece of rendered markup that is present in the non-ARIA-enabled version.
Ideally, when working with screen readers, we would like to see something like the following behaviors:
* The number of items are announced when results are loaded, including empty results
* Each item is announced as the focus is moved through the list
* The selected item is announced when picked or whenever focus returns to the field.