Alright, here are a few things to think about before upgrading to 12.04 regardless if you're completely comfortable with Ubuntu or not. I just finished my upgrade from Xubuntu 11.10 to 12.04 even though the upgrade manager calls it an Ubuntu 12.04 upgrade (understandably so). Today was the first time since Ubuntu 9.04 that I used the Update Manager to do everything automatic by clicking the upgrade button. I keep referring Linux/Ubuntu to others, even Seniors, and I wanted to make sure that I can safely recommend the automatic upgrade ... which sad to say, I can't.
In the past I always backed up my home folder (all of my other stuff is on external drives anyway), followed by installing the new upgrade from an ISO image on DVD. Another reason why I didn't do that this time is because I've really customized my desktop and didn't want to spend an hour to an hour and a half reconfiguring my 6 custom panels, personally created icons, and so on. As far as timing is concerned, that would have been a far better choice ... even though my automatic upgrade worked flawless with zero problems the first time around.
Okay then, so why wouldn't I recommend the automatic upgrade option?
In my opinion an automatic upgrade should be exactly that, in order to avoid confusing any (millions) users with commands that they may not be familiar with. There's just no point to an automatic upgrade if it isn't actually fully automatic ... click the button ... go to bed ... wake up and everything is fine (or not) ... For someone with little experience the fresh ISO installation would be better choice (even for beginners) because it would save literally hours of your time while possibly being less confusing too. Remember, I stated that I had zero problems with the upgrade, but here's what I experienced from beginning to end ... which took 5 hours and 50 minutes on a 40 mbps connection, beginning at 07:00 AM this morning Eastern time (04:00 AM California time).
First, keeping the terminal view option (tiny arrow, left side) open during the upgrade proved to be a lifesaver because when libc6 was being retrieved, the upgrade process literally came to a halt. I didn't notice it for about 15 minutes, so that's when I opened up the terminal option only to find that there was a prompt which required me to hit the enter key for OKAY. Had I not done that, I'd be sitting at that spot right now over 6 hours later. This was followed by 2 or 3 more okay functions that I had to respond to within the following 5 minutes or so.
Then, about 5 hours later I had to respond to a query about my old Network Manager. A little while after that I had to respond to a query about my Grub configuration which might have turned into a nightmare for any inexperienced user who's hoping that the automatic upgrade button does exactly what it implies. Luckily those last two queries appeared in a small window so that couldn't be missed like those first few queries.
Aside from compiz there are no other oddball applications (heavy 3D games, Wine for Windows compatibility, Virtual Box, etc.) on my machine. So again, I want to stress that the upgrade did complete perfectly after almost 6 hours (already compensated for the lost 15 minutes). If I had done a clean installation from an ISO image the installation would have taken roughly 30 minutes, followed by an hour and a half or so of customizing, installing backed up applications, and so on. So either upgrade option appears to be just fine, as long as you're aware of the fact that A. the automatic upgrade takes substantially longer, and B. you'll need to keep the terminal view open during the upgrade to make sure that you don't miss any important (clib6) prompts.
So should you upgrade at all? Well, I can't speak for anyone else but my computer which was already really fast to begin with, now appears to be even faster yet. No regrets, I'm happy. But if you're already content with your current setup, then you might want to hold off for awhile and enjoy that which is already working for you. I hope this helps someone ...