I am not sure if you have seen this but below is a free screen reader review in the braile monitor about NVDA. https://nfb.org/images/nfb/publications/bm/bm13/bm1305/bm130507.htm and here is the Mp3 version. https://www.nfb.org/images/nfb/audio/braille_monitor/2013/may/09_my_search_for_accessibility.mp3