I've been playing with Vista the past few weeks since it was released to manufacturers... There are a lot of quirky things to it.
What I found to be the funniest yet, has been the way Microsoft dealt with some of their new folder arrangements. User profiles are no longer stored under "C:\Documents and Settings\" now they are under "C:\users" - so in a desperate attempt to work with poorly written older applications Microsoft places a hidden shortcut named "C:\Documents and Settings" that basically points to "C:\users" ...
There are quite a few of these hidden shortcuts all over the place which basically tell me that for a while there will be this 'patchy' arrangement where holes are covered up with shortcuts to the new os defined paths... Hopefully what I said made sense...
Usually if a driver installs services (like my lexmark printer for example) you have a pretty small chance it will work on vista.. There are also annoying things like hardware incompatibility issues that still occasionally cause blue screens for that classic Microsoft moment...
I found it most frustrating that installing Visual Studio 2005 does not work very well. You have to go out of your way and apply a work-around to get the desired compatibility.. All the compatibility issues are understandable, but still pretty frustrating until new software is released with vista in mind..
There are a lot of features really that I found pretty cool to have built in, but at the end of the day - you're paying for a more reliable and secure operating system with a rich UI..
I hate to say mac did just that a few years ago.. Maybe I haven't compared it well enough yet - but overall thats what I got out of it so far. For windows people its a great improvement. But mac users kinda had this already...