Ah, perhaps I've found a possible reason some are reporting that the player "goes back" to the original?
I had the list of streams for my area pulled up, opened the Java player in another tab. Had some funky trouble at one point (more on that follows) so I closed the player tab and reopened it from the same stream list in the original tab. I could only get the original Flash player, even when I selected Java player from the pulldown list. Reloading the page let me select the Java player again.
Now, the funkiness that started all this: I started to get echoes. Someone would start talking, then a few seconds delayed the exact same audio would come across again. That could have been something on my end - I was fiddling around with some browser settings and the player page got reloaded (like hitting the Reload button, but that's not what I did). Maybe two instances got loaded up, one slightly lagging the other? At any rate, closing the tab killed them and the newly reopened player is working fine.
This is all in Firefox on XP.