I was trying to migrate my HD on my G5 to my new iMac. Although I finally succeded in target mode, I could not transfer my mail and bookmarks, and various other settings, and just about all my preferences. After two days and many hours on the phone with Apple, following my inability to install updates or apps (message was that I did not have sufficient privileges), I was told to add a new user account. Once I did that, I could install, but I still could not bring over my mail and bookmarks without "importing" them. I have read in many places that dragging and dropping them from one computer to another worked for them - ie: swapping out the mail and bookmarks files. It does not work for me.
To top it all off, following the target transfer, I woune up with my G5 being "renamed" since the original name already appeared on the network. I got that message on both computers.
New issue - the iMac runs very hot - especially at the top - almost too hot to touch. Now I have something else to call about, since I have read conflicting reports on it - some saying it's not a problem, and others saying it is.