Yes, distros talk about accessibility improvement, but we are still
a bit far from _real_ mainline accessibility. GUI accessibility is
still some mess, but hopefully with firefox 3 integrated in all distros
the web part will work nicely.
About the bugs & such you encountered, that's unfortunately mostly
because distributions haven't yet done their part, integrate components
together, so that you have to mix things together by hand.
Now, what you tried was GUI accessibility, which is quite recent. Try
CLI accessibility, _that_ has been working for more than a decade now;
so you can say a linux _text_ system definitely _is_ accessible.