Ubuntu 10.10 installation on my Acer desktop is rather smooth. I was using upgrade install for the 10.04 LTS release. Since there is an empty partition this time (giving up FreeBSD), I am using fresh install this time. Firstly I downloaded the ISO, installed it to an 8GB USB Flash Disk, boot the USB drive, played a bit with the live session. Then I installed it to the empty partition. It was a very smooth process.
Still the open source Nvidia driver is quite flaky (even the font it not clear) for my old shared Nvidia graphics card, so I opted to install the proprietary driver which is much more usable. After switching to a normal theme (to be able to close the window from the upper-right corner) and disabling the visual effect and installing a bunch of software packages, I am in business. Thanks to the fast broadband (16Mbps) and fast Ubuntu Singapore mirror, the whole process is actually not long.
As for the first impression, I have not yet noticed any real difference. It is just quite smooth.