I was bracing for the worst based on past rollouts from Microsoft. After experiencing the pain of Vista, I was quite apprehensive about the release of Windows 7. Even though there was good press (which I don't put a lot of faith in anyway) I knew there would be some serious bumps in the road to transition.
My first 4 or 5 installs went off without a hitch. Many of my customers were upgrading old Windows XP machines that were 6 years old. The new computers with Windows 7 had fast processors, more ram, and dedicated video cards, which helped a lot. The boot and shut down times were greatly reduced and the most popular software seemed to work right out of the box.
I didn't recommend upgrades to current equipment and most people went with the advice. Life was good and customers were happy. Since all of the installs were new computers and not Vista upgrades, none of the upgrade problems were an issue. There were quite a few problems found on the Vista upgrades, especially those who downloaded the Windows 7 install. The files wouldn't unpack properly, refused the new product keys, and had some rebooting problems. Then there were the unspecified errors and directory permissions problems. But all were confined to the upgrading Vista process, many due to reformatting the hard drive before the new install.
If you are upgrading a Vista machine, don't bother to reformat the hard drive before you upgrade. It appears that this is a problem. You should do a clean install and let Windows 7 format the hard drive in the process. That method appears to have few of the issues that the clean hard drive upgrades have and you still get a new clean system.
Then it happened, I found a nasty little problem on the new computers with Windows 7. Bringing in a new Windows 7 computer into an existing network worked fine as long as you stuck with the workgroup name of workgroup. But if you had a different name (which many clients do for multiple reasons), the Windows 7 computer was seen by the others in the workgroup but couldn't connect or see any of them.
I did a little research and talked to some other techs and they were experiencing the same problem. Not good, most clients didn't want to change their workgroup name. There was a work around by making every computer also a workgroup member and the original name. But it wasn't a great solution and might come back to haunt the client and me some day. =
Another big issue with Windows 7 was the way it stored files. They went to a library system, which is a common method on the Macs and Linux machines. Once you get it, it's probably a better method of organizing files. But when you introduce it to the user and a bunch of older Windows XP systems it can get confusing. When you change something as basic as how you view and store files, and you have a lot of shared files, users don't always adapt quickly.
Automated backup systems have to be changed around and tracking changed files gets a little more exciting but with a little training and automation you can over come the differences. Most users are over worked these days and some aren't all that willing to change. So it's both an operational and an attitude you get to deal with when bringing Windows 7 computers into an existing environment.
And, don't believe what you read about the Windows XP Mode. Many older computers aren't compatible with the virtual machine methods used. About one in three of the computers I've tried to set up XP mode couldn't do it for one reason or another. New machines often have all the necessary bios settings, chip sets, and other requirements but older computer may not. When it works, it's great. But don't depend on it until you have tested it on the computer you want to run it.
Most of the other issues are basic configuration changes that default on a new Windows 7 install. For example the taskbar looks and acts different and many users are complaining they can't see what's open at a glance. There is a way to change the toolbar back to what it used to be by right clicking the toolbar and selecting properties. And make any changes in appearance you want.
All in all the Windows 7 transition and open issues are no where near what the Vista debacle was and most are easy to overcome. And if you don't like a particular feature or display method, most times you can change it back to what you want it to do or look like. The speed and faster boot times are more than worth the hassle of reconstructing your desktop like you want it.