I am a software engineer by trade so having a stable system is something that is a very high priority to me. I was one of the first to jump on Windows Vista and I must say, I was not satisfied. I continued to use Vista (64 bit) on my main production machine as long as I could, but I eventually did what many other before me. I reinstalled my machine and put Windows XP (64 bit) back on it.
When Windows 7 beta was announced, I installed it on my test machine and I was impressed how well it functioned in beta. However, I decided to hold off on installing it on my production machine until it was a more stable release. Once the RTM was available for MSDN subscribers, I immediately downloaded it and installed it on my production machine.
It has been running on my production machine for a couple of weeks now and I must say, I could not be more impressed. It has not crashed on me one time and it seems to be rock solid. The install did not come without a few headaches though. While many of my headaches were most likely due to it be a 64 bit install, overall the process went really well.
The biggest complaint I had was the fact that you cannot upgrade from XP directly to Windows 7. They force you to do a clean install which means you must install all of your applications again. They do provide a tool that will allow you to copy your personal settings over which works really well.
Since the install I have been able to install all of my applications and everything is working properly. The only driver that I had any real problems with was my sound card. Windows was not able to identify my sound blaster sound card, but after contacting the manufacturer, they were able to provide me with the driver needed and it has been working perfectly ever since.
Overall, I would recommend everyone upgrading to this Operating System. Microsoft has delivered to the task at hand this time. This is a rock solid operating system and the early signs show that it will be the operating system of the future.