Ubuntu Lucid Lynx is now out of beta and in the wild for the general public as a finished product.
I have personally been waiting for this release since about November of 2009.
The predecessor for lucid was somewhat of an unloved child. 9.10 Karmic Koala had many new features. many of these features were not complete or did not function correctly. Karmic was not ready for release when the deadline elapsed. As a result it's entire lifespan was a torrent of updates, desperately attempting to fix the situation.
Over the last couple of days I have updated both the dual core 64 bit AMD based desktop and my 32 bit netbook to lucid to see how well it's updater works.
The update is relatively painless and almost everything still works perfectly. the updater does ask questions which the novice would find utterly daunting such as which device and / or partition to install the bootloader and whether to remove unsupported programs.
On the desktop it grumbles a little about USB on startup but everything seems fully functional which I would consider a win.
On the netbook there are a few issues such as no splash screen and a slow-ish boot. But once again everything is functional.
I would recommend doing a clean install if possible to avoid upgrade-itis.
Is it worth upgrading from Karmic?
Yes. The positives far outweigh the negatives. SMB file sharing seems to be working properly again. USB drives haven't been glitching out and changing permissions at random.
The context menus in nautilus have been expanded and integration with Ubuntu One, an online storage / sharing system has been improved.
I could go on, but I feel the best way to explain it is that Lucid is to Karmic as windows 7 is to Vista. Not a total revamp but a lot of subtle repairs and upgrades which go towards making a far less frustrating user experience.
The only complaint I have is that the window buttons in Gnome have been moved to the left. Thanks for that Shuttleworth.
It is possible to move them back with a file edit though.
i was so close to moving back to another non-Ubuntu based distribution because of Karmic. I was even trying other distributions and operating systems. However Lucid has stopped me. To be honest I only upgraded out of morbid curiosity, expecting a tragic unworkable mess. After using it for a while I was pleasantly surprised as it would seem Ubuntu's fall into decay and ruin has been halted.
I would recommend lucid to existing users and to people who are curious about Linux.
To the curious, there are live CDs available which let you try it out without affecting your system. The downlaoded image can also be put on a USB drive or SD card and optionally set up with some persistent storage so other programs can be installed and your files can be kept. great for system recovery or just taking your system with you.
My conclusion: Lucid is good. Try it.