The RTM pressing is usually sent out a couple months before the "release date" ... Even then, XP was probably one of the worst at release, and wasn't really okay until SP1, and good until SP2, but people forget that. Vista was pretty bad too.
The only version of Windows in my mind that worked really good out of the box was Windows 2000 (not ME), and even that had a conflict with some piece of software (cd burning program iirc)... Also, they removed the in-memory database between the final RC and release, which irked me to no end.
I didn't really start using Windows 8 until 8.1, I touched a few machines (that didn't have touchscreens) with windows 8 early on and it sucked, server 2008 over RDP was worse... 8.1 with classicshell isn't bad.
