using xine makes amarok extremely unstable on my computer though xine as audio and videoplayer itself is stable and never causes problems.
For example amarok crashes after 15 minutes playing without an obvious reason or it crashes after klicking on pause or hangs and blocks all keyboard-input, so that it's not possible to kill it and reboot is needed.
After changing to helix, amarok is pretty stable (though not perfectly stable), but helix doesn't have as many features as xine...

Does anyone else have these problems too?

Sounds like your xine-lib is broken. Upgrade to 1.1.2.

Also try to disable crossfading. With some broken ALSA setups it can be problematic.