answer:I updated about a month ago and not had any problems with compatibility, pretty much everything upgraded itself automatically. The upgrade feature is very user friendly however it does take some time, the download will be about 700mb I imagine then the install and upgrade another few minutes probably a 30min-1hr process depending on your internet speed and PC however you can continue work as usual while its all in progress. If you backup your home folder then you will maintain your settings and files should the worst happen however I should stress that when you upgrade Ubuntu will maintain this automatically. 10.04 is noticeably faster and apps load faster in it. It also has a few nice modifications, but as always nothing in your face has changed. Expect 10.10 later in the year to be quite different :) 10.04 has more of a Mac feel to it also supports much more plug and play items than before.