My brother-in-law is blind, so I've been interested in linux accessibility for a long time. Not interested (or talented) enough to actually improve accessibility, but interested enough to keep an eye on the matter.
Long ago, I couldn't get Festival or Orca to work at all on my laptops. Mainly hardware support issues. One particular problem had to do with the software requiring the audio card to allow sampling at a rate that was twice what my audio card could do.
I just tested Orca on Lucid though and it's looking very good. Just enabling Orca took all of 5 seconds. I was a little confused since some things worked (firefox and the Orca preferences) and others didn't (gedit, gnome-terminal running man). Logging out and logging back in fixed that. I suppose just enabling Orca but not restarting didn't allow Orca to get its hooks deep enough into Gnome so it could intercept X11 display and keyboard/mouse events.
It took a few retries and hour and a half to get a reasonable set of Orca flat-view keybindings that didn't conflict with the regular gnome keybindings. I like using the Windows key (Super or Super-L) as a command key for Orca since it isn't used in Linux, exists in all new keyboards and is convenient. I don't much like Orca using the Caps-Lock key for that. Using the Windows key would be a problem if Orca ran in Windows but as far as I can tell (from the Orca website it doesn't run in Windows.
I was a little confused that Orca had firefox-specific keybindings, but they probably had to implement that to have similar behavior as JAWS (the dominant windows screen reader, and therefore the dominant screen reader in the world).
So Orca has some generic keybindings for general flat-view and other functionality. It can have app-specific keybindings. And it's scriptable (says the web page, although I haven't looked at what scripts might look like or how powerful they are).tt
It's also been pretty stable (tested on three laptops, all of which are pretty old). The only instability I saw happened when trying to close the Orca program via the GUI. Gnome and X hung so completely I had to go to a terminal and kill/restart gdm.
That's no big deal though since blind people would normally *always* have Orca on. And when I killed Orca from the command line (orca -q), it died gracefully and didn't take Gnome or X with it.
But all I've done so far is play with it a bit. I haven't used it extensively at all. Instability might become a lot more noticeable after hours or days of use. Maybe I'll try to get my brother-in-law to test-drive it on one of these laptops (instead of his Windows+JAWS laptop) for a day or two.