You should not take Mike's problems described in his article as representative. I had no issues upgrading my PC to Windows 7 Home Premium 32-bit, but I did a clean install.
Don't take Thomas' as representative either. Getting a feel for how Windows 7 is really doing requires research: things like what OS and software you are using now, whether you are going to do an update or a clean install, and whether you are using 32 or 64 bit all factor into the equation. We're still early in the transition but I have found some common issues that are fairly significant and have been corroborated via other users. The two main ones are:
(1) Windows 7's folder/file security is EXTREMELY non user friendly and buggy. Doing something as simple as restoring a folder of files can cause some or all of the files in the folder to not be readable, even if you have admin privileges. Using the Windows "Properties" function, you'll find that if you select one file at a time, you can get to the "Security" tab where you'll need to delete all user access and add back the ones you want and take ownership of the file to correct this problem, but if you select more than one file, the "Security" tab is often missing, forcing you to do this one file at a time. Worse, this seems random, where multiple files of the same type and same (current) privileges will cause the "Security" tab to disappear, while other multiple selections do work. It's an absolute mess. Setting security at the folder level says it works, but it doesn't: it randomly leaves out certain files in the folder and doesn't change them. You can end up with a folder that you own, with simple files like JPG images or text files, and
some of them won't open even if you open an explorer window in "Run as Administrator" mode. I actually had to make a command line batch file to fix the problem.
(2) The longer you run your machine, the more instances of "Explorer.exe" will be running in task manager. I've found as many as eight copies open, each using about 15 MB of memory or so. Only one is the "correct one" that shows you your desktop. The rest are W7 memory leaks!
Update: I actually located the problem with this one. If you create an Explorer shortcut on your desktop using any of the Explorer startup switches, you get a new Explorer process each time you click on that icon... and they all hang around and never close even after you close the window. As an example, just create a new shortcut using "%SystemRoot%\explorer.exe /e,/select,c:". Now each time you click on the icon you get a new Explorer.exe process that won't go away unless you kill it in Task Manager. If the shortcut is just "%SystemRoot%\explorer.exe" without the switches, it works OK. Again this is with W7 64 bit. Doing the same thing on Vista 64 bit leads to no problem: you do get an extra "Explorer.exe" process each time you open but they go away as soon as you close the Explorer window. Just one of a number of W7 bugs that make even the most basic of OS operations painful. W7 just was not ready for prime time: as of this writing, it
still isn't!
As I said, a lot of factors contribute so you may or may not see these problems, but they are common.
Mike