I have just upgraded from FC6 to F7 on my Sony VAIO. I would normally tend to do a fresh install as I did on my Desktop but remembering the pain I went through to get my wireless LAN to operate on my VAIO, I opted for an upgrade, hoping my wireless would be left unscathed by the upgrade.
Well, I had no problems. I just had to modify grub.conf so that it points to F7.
What worked before still worked. What did not work before still does not work (function keys, mainly).
I am thus a happy F7 user.