Checking, I find it interesting that I can go from F 10 to 12 now, with preupgrade. I skipped 11 because the number of people posting with install issues didn't drop off after the first week or two. I've got 11 on my laptop, however, because 10 was badly unstable on it. Will use preupgrade on it, RSN, as an experiment. If all's OK, will do my desktop, probably next month. (Right now, I'm busy with NaNoWriMo, and don't want to mess with my main box if I don't have to.)
Registered Linux user #470359 and permanently recovered BOFH.
Any advice in this post is worth exactly what you paid for it.