What sort of system? It does take forever in my experience.
mine been stuck at the login for over 2hours
have to say mine was quite quick took about 30 mins to download and install.
Got my upgrade lats night 3.6GB download, was quite quick to download. Installation was 10-15 mins.
I have heard that its slower for machines with lots of programs and apps on them. I formatted a few weeks ago so I am pretty clean.