Canonical has constantly been playing with the notifications. Each
version is slightly improved. It makes it hard to give advice to
someone using a different version because the changes are often
subtle. Sometimes it has been a vertical drop down and sometimes
horizontal. Sometimes the names are slightly changed or features added
or removed. I like what they have now, but I am using KDE 4.6, and
10.10 has just 4.5. For those of us who change frequently it is often
hard to remember what it looked like before.

Of course, Ubuntu users are in for a big change if they upgrade in the
spring. Unity or GNOME Shell will be very different from GNOME 2.x
which they have now. Kubuntu users can look forward to KDE 4.6 and it
is just a bit different and nicer than 4.5. The big difference is that
Kubuntu has been through the change a couple of years ago that Ubuntu
users are going to go through. We can be sympathetic because we know
what radical change is like and how it can affect the user. Two years
from now we will all wonder what the fuss was about.

On the notifications issue that you raise, Fedora and openSuSE are
looking at Ubuntu/ Kubuntu's notifications for use on their desktops,
so they must be good.