The Release Candidate for Ubuntu 9.04 was made available yesterday, and I have now installed it on all four of the laptop/netbook systems here. As usual, it is just really good. Installation is smooth, easy and fast, and contrary to some grumbling on the web, I think there are a number of nice changes and improvements in it.
The first, and probably most obvious, change is the improved boot speed. It boots in 30 seconds or less on all four of my laptops! Since this is now the Release Candidate, and the final release is less than a week away, I think it is safe to say that they are not likely to lose that boot speed because of other changes before the final release comes out. Hooray!
Of course, this release includes new versions of all sorts of packages, ranging from the Linux kernel itself (2.6.28), the Gnome desktop (2.26), X.org server (1.6), and various others. Two of my favorites, though, are improved handling of multiple monitors (I use this all the time with my laptop and an external display), and an updated openchrome driver, which makes installing it on the HP 2133 Mini-Note just about as easy and routine as it is on any other system (you don't have to download, compile and install the latest driver yourself).
Jaunty also includes full support for the ext4 filesystem. By full support, I mean that both the Linux kernel and the Grub boot loader understand ext4, so you can use ext4 for the entire installation. The general wisdom is that ext4 is faster and more reliable than the current standard ext3, and is a likely candidate to become the standard in the future.
The release notes also say there are changes which are more server-specific, such as integration with cloud computing, and an improved mail server. I have not had occasion to deal with those yet.
If you are really anxious, you can get the Release Candidate now. Those who are more patient might want to wait just one more week, as the final release is scheduled for next Thursday, 23 April.