I did not migrate anything. I put a few of my applications on the fusion drive but the wifi failures kept breaking the internet connection so that my creative cloud apps would not fully download or deploy, Dropbox is also affected by the wifi failures.
There is almost nothing on the machine but what came installed, yosemite and the i program suite. I have not used any of the i suite programs because they do not work with the size of the documents I need to use, and they need apple Dfonts to work, which do not print in a professional postscript environment. They are only made to function on a mac. Occasionally, if I know I will only give a presentation on a mac, I use keynote, but most clients want powerpoint.
the wifi failures are affecting all the other wifi devices in our studio. If I turn off the iMac5k, the other devices using wifi and bluetooth and airplay work as expected. When the iMac5k is on and wifi is enabled, everything starts dropping. I am keeping wifi disabled and wired browsing is still affected once in a while.
Because I work on material from many different sources, I use different versions of adobe software to preserve the integrity of the different files I am given. Because of what you have just told me, I will only purchase mac computers with multiple hard drives from now on. A separate hard drive with each of the systems made while the machine was manufactured is allowed, and that is what I will go back to doing.
The other reports of wifi issues from other users are widespread. I look forward to trying the upcoming 10.10.1 or other update before I take the machine anywhere.