While Vista officially shipped at the end of January, 2007, I've had nothing but frustration with its reliability since I got it with my brand new laptop. I've really had a bad experience with the product. I've had random hangs of various applications and its been rather frustrating. Honestly, the product felt very much like it was rushed out the door. Granted, I am a developer, but I could hardly go an hour without a crash or a hang. Then, last week, like a bolt from the blue, MS released the new performance and compatibility updates.
I installed them and it was like night and day difference in my system. I'm not quite sure what exactly this resolved, but since then, I haven't had any issues. This has been awesome. Its like Vista has finally shipped.