Why is the iPhone 4.3 update taking SO LONG to download?

I have the iPhone 4 and just attempted to update my phone at my friends house to the new 4.3 update. It was saying the update would take 2 hrs at first, the 10 minutes later it was saying 4 hrs. The download time continued to increase and after it reached 9 hrs, I cancelled it. I then plugged my iPhone back in and selected to only download the update and I will install it later. This method also had a 9 Hr completion time, maybe more by now. My friends 3GS took roughly 4 hrs to update earlier.

Can anyone explain what the problem may be? It seems everything is up to date on the laptop. Is anyone else having a problem with downloading this update?