I'm still seeing a wide variety of results when people try to update to Windows 10. I was not able to help the customer mentioned in my last post. He called again after several more hours of waiting to advise that it failed due to numerous errors. Two other customers have called to let me know they did the update without a hitch.
I'm currently onsite setting up a new laptop with Windows 10. While it was downloading and preparing to install I was able to install the printer, install Office 365, install iTunes, install Internet Security and transfer 65+ gigabytes of personal data. Now I'm waiting for the Windows update to finish. It's been 3-1/2 hours so far and I'm predicting 45 minutes to finish up.
This is on a brand new Dell Core-I7 with 16 GB of RAM. My suggestion is if you want to do this upgrade, be very patient.