I upgraded to Windows 7 on my laptop yesterday. Overall the upgrade went smooth but it was time consuming (About 3 hours, of course I have a lot of stuff on my laptop). I think the average home user will probably not upgrade to Windows 7 but rather acquire it through a new PC purchase. That's probably a good thing for the end user.
Here are few things I noticed during the upgrade. The first thing that jumped out is that the upgrade process is still not geared towards the average end user. The upgrade process is going to do a compatibility check before allowing the upgrade to proceed. If it finds things that are not compatible it's going to ask you to uninstall them. While not an issue for an IT person like myself, I suspect an average home user is now confused. Especially when it asks you to uninstall your wireless network card. I did like the fact that it tells you iTunes is probably not going to work correctly anymore. Nice marketing play there Microsoft. Of course it works fine after the upgrade.
On the positive side, Windows 7 takes up less memory and runs a bit faster. On the downside they got rid of their little built in mail client which is a bummer. I liked that client, really don't like web mail interfaces, sorry Google but I like to work disconnected sometimes. Plus I don't like a million things on my screen other than the email when I working on email. I know there are a million email clients out there to be had but I liked that one, it was simple and efficient.
It did detect all my hardware and configure it correctly which is a step up from the past. The interface is clean and seems to be pretty logical. Overall I'd give Windows 7 a thumbs up. I'll post back any observations as I get more accustomed to it in the coming weeks.