I don't think many people realize this is a GREAT thing for people with visual disabilities who want to use a Mac!!! For many years there have been almost zero options for third party screen readers for Macs. All the developers of these types of apps have dropped Apple some time ago (out of economic necessity) and if you are blind or visually impaired, your only option is a PC with JAWS, WindowEyes or a few others. In addition, this will help Apple meet Section 508 and other accessibility laws for selling technology to the government.
If you think the keyboard combinations are difficult, try out the JAWS demo. JAWS users are required to memorize up to 250 JAWS specific keyboard commands + another few hundred for Windows, Word, Outlook, IE, Excel... where the organization of these shortcuts is an absolute mess. Of course you can get by with fewer keyboard shortcuts, but to do all things I do and most of us do, you need most of them. Either way, the demands on attention and memory (not to mention typing skills) far outweigh anything people with vision have to deal with in using a computer, but I'm betting the Macs more consistent and well thought out UI will end up being more consistent and therefore easier to use for people who are visually impaired - as long as Apple did this right.
If you *really* want to try Spoken Interface as it is intended, turn OFF your monitor then give it a shot. Then try the same thing with a Windows screen reader. Realize you probably can still imagine what is happening visually on the screen and this gives you a big advantage over its intended users.
P.S. I worked with people who are visually impaired and their accessibility software for three years. I think it is safe to say the average person thinks all this stuff works wonderfully and has basically solved everything, but that is far from the truth (Hollywood hasn't helped this point of view and most people I know who are disabled get a big kick out of movies where accessibility software is so powerful). The thing to realize is that making something accessible does not always = making it usable. Believe it or not, DOS and command line interfaces + screen reading gave people who are visually impaired nearly equal access to sighted people (almost level playing field in terms of memory demands). When the GUI came out, it made things far more complicated and far less "linear" for people with visual disabilities.
I once compiled a database of all the keyboard shortcuts for JAWS and all Miscrosoft office apps (including Windows, IE and Outlook) and did an analysis of all duplicates and inconsistencies among the nearly 1100 keyboard shortcuts. In addition, while in graduate school for Human Computer Interaction, I did a usability analysis of accessibility tools including screen readers (JAWS). Apple (and their 3rd party developers) led the world in accessibility back in the 80s and I am really happy to see them back in the game here. This area REALLY needs a fresh approach and I think Apple can show up the rest of them - mainly on the superiority of their underlying UI.
Here are some links:
http://www.section508.gov/
Screen Reader demos if you have a PC
http://www.gwmicro.com/demo/
http://www.freedomscientific.com/fs_downloads/jaws_form.asp
http://www-306.ibm.com/able/solution_offerings/hpr.html
If you don't have a PC, (congratulations!) here is a web based screen reader simulation site (I have not tried it out):
http://www.webaim.org/simulations/screenreader
Though not a screen reader, Kurzweil 3000 is the coolest app ever made for people with reading disabilities. Kurzweil 1000 is a similar app for people who are visually disabled. Check the online demo to see some really well thought out and powerful technology:
http://www.kurzweiledu.com/k3000demo/
P.P.S. One more thing and I will get off my soap box
- Accessibility is a valuable thing for everybody. When you evaluate a UI from the standpoint of someone who is disabled you really "shake it down" to core interaction design issues (for example, the jumbled mess of keyboard shortcuts in Windows) and, from my experience, this is where Windows bashing is fully justified - Windows underlying poor usability becomes even more apprent when you try to make it accessible. Making things accessible can lead to making things far more usable and versatile for every user.
