It's 10 days since I uninstalled Windows 7 RC from my laptop and replaced it with Mint, a Ubuntu derivative, and so far I'm happy. I was happy enough also with Windows 7. I think it's a great operating system, and the best Microsoft has produced so far. But to continue using it - according to Microsoft - I would have had to uninstall the release candidate version and replace it with a new version. i.e., it would not have been possible simply to update Windows. And then there's the cost. I hate "crippleware" - software in which some features have been deliberately disabled, but would also have been unwilling to pay the high price Microsoft wants for its full version.
So I installed Linux Mint. It's based on Ubuntu, but is designed rather attractively by its Irish developer. The graphical user interface is closer to Windows Vista, though it has a flavor of its own (mint flavor I suppose). Installation was very easy, and I haven't been forced to do anything terribly complicated to get things working as I like. There was a small problem with the wifi - it worked but kept cutting out. In a forum, someone suggested replacing the native Ubuntu wifi handler with Gnome's WICD. I did that, and it worked fine.
I also fiddled a little with the fonts. Before downloading MS core fonts (like Arial, Times New Roman, etc), there was a problem with some browser fonts - like Arabic - being over bold. After installing the Windows core fonts, this made the system fonts a little gritty, so I took a backward step and brought the system fonts back to normal. Now all my fonts are at least as beautiful as in Windows. They are actually a little nicer.
I also had a little problem with my 2 Brother inkjet printers (DCP 130C at work, DCP 150C at home). Installing the files from Ubuntu's repositories worked, but then I discovered the margins were off. (Tip: to check that, get OpenOffice to print a page border.) So I downloaded the Linux drivers from Brother's website instead. I also installed the scanner drivers, since these printers are multifunction devices. It was a joy to be able to scan directly to PDF again, using gscan2pdf.
The best thing about the change to Mint is how zippy my machine has suddenly become. I had gotten used to the sluggishness of Windows 7. And now even a heavy program like OpenOffice is opening almost instantaneously. The same is true of file viewers, browsers, graphics programs, etc. The only unfortunate thing I have noticed is that music slurs a little when I'm doing heavy file operations like copying directories back and forth between the computer and an external hard drive.
Speaking of which, it's always dangerous to move files off a comptuter in order to reformat it. I lost a number of files due to Windows 7's Libraries feature. I somehow failed to copy every directory in the library. Moral: when backing up files, it is better to do so from native directories, ignoring Windows 7 Library shortcuts.
Every few months I dither between Windows and Linux - but every time I return to Linux it has gotten a little better. And Mint is just super! The change was worthwhile.