The installation with Ubuntu 9.04 (used beta first and then updated nearly on a daily base) went smooth so far. Frankly I did not expect otherwise. I had no issues during the installations.
However, there is one backdraw when actually using it. While most or actually Hardware is working the sound chip seems to be too new for Alsa 1.0.18 which ships with Ubuntu 9.04.
I had to install Alsa 1.0.19 which I did using a script mentioned in the ubuntuforums.org. After that most of the time the sound works. After an unregular period of time the sounds starts to stutter and even refuses to work. However, this is easily solved by a force-reload of alsa.
It is not nice and I am unable to determine if it is a faulty implementation of 1.0.19 or if I will need to wait for newer releases to fix this issue. But so far I can cope with that.