Currently, most blind people on Windows either use JAWS or NVDA as their screen reader of choice. If testing on desktop, I recommend NVDA over JAWS, because JAWS often makes guesses about content to improve the user experience that can negatively impact testing results. If testing on mobile, I recommend VoiceOver for iOS, as this is the most prevalent platform used by blind individuals. Here is a summary of some of the best screen readers available today.
NVDA is a screen reader that is heavily used by blind individuals on the Windows operating system. This screen reader has been rapidly gaining popularity in the past few years due to it being free and open source as well as rapid improvements being made to the code.
NVDA supports Windows 10, Windows 8.1, and Windows 7, and all server operating systems starting from Windows Server 2008 R2.
JAWS has been available for many years and is a commercial product that can be purchased from Freedom Scientific, part of the VFO group. It is popular because it has name recognition from being available for many years, and it supports many bespoke applications via scripts.
JAWS supports Windows 10, Windows 8.1, and Windows 7, including touch screens and gestures.
Narrator is a screen reader produced by Microsoft and built into Windows 10. Although it has been around for a long time, it has not gained a large number of users. Until recently, Narrator was only a basic screen reader, essentially included to help the user install the operating system and then install a screen reader of their own.
In the Windows 10 April 2018 Update, Narrator has gained a lot of functionality and can now be used to browse the web in Microsoft Edge, as well as to interact with files in Microsoft Office and modern Windows Store applications. Because of the new functions being added to Narrator, it is gaining more users.
VoiceOver is a screen reading application available for MacOS and the iPhone/iPad, and it is included within the operating system. This screen reader works best with Apple software as well as Microsoft Office and Google Chrome. It is worth noting that, like Narrator, there are many instances in which third-party apps—created by vendors other than Apple—do not work well.