There are two problems with those mainboards:
1. The SATA contoller (690G) does not work properly with the driver of the slightly outdated kernel version, this wil probably get fixed when there is a release for Kubuntu 0710 (or you can rebuild the kernel with a small patch).
2. MythTV did not work with the integrated graphics (x1250) chipset due to ATI driver issues, I don't think this issue has been fixed already in the latest ATI drivers but hopefully it will be in a nearby future release. From what I've understood they are making good progress, so who knows.
I was foolish enough to buy one with the same chipset, see also the Asus M2A-VM motherboard page in the wiki for more info.