I upgraded to Feisty about a month or so ago, and it has been a nice improvement so far. One regression I noticed though was that my USB FM radio tuner had stopped working (or at least, Gnomeradio could no longer tune it).
It turns out that some time between the kernel release found in Edgy and the one found in Feisty, the dsbr100 driver had been upgraded from the Video4Linux 1 API to Video4Linux 2. Now the driver nominally supports the V4L1 ioctls through the v4l1_compat, but it doesn’t seem to implement enough V4L2 ioctls to make it usable (the VIDIOCGAUDIO ioctl fails).
To work around this, I ported the tuner code in Gnomeradio over to V4L2. The patch can be found attached to bug 429005. I don’t know if this patch will go in as is though, since it only works for drivers supporting V4L2. Perhaps it’d be worth supporting both APIs, using V4L2 if both are supported.