Recently I installed Karmic Koala 64bit beta version in my laptop(HP compaq 6720s) and it's really awesome. The graphic issues which I had in jaunty seems to be gone with the new system works fine with Intel 965 chipset. And there are some major changes like Grub2, upstart, Telepathy which needs some time to get familiarise with. Hope to write more on this new experiences and how to get work done. For a list of changes follow this link
BTW I had some issues with broadcom wireless card but it may be because this is beta version and with the help of a wired network it was quickly solved. We have 13 more days for the final releae and I really like to say THANK YOU for the all the people who put there valuable time to bring this awesome operating system to the community.