Those who have already upgraded to Lion have found some problems. John Carter comments, "One thing to note, is that Picasa can no longer access iPhoto library. We’ll have to wait for an update to Picasa for that fix. There are other bumps, in particular with Parallels. If you’re using Parallels with Windows (any version) be sure to only open the guest OS in the Coherence mode. You’ll go crazy trying to figure out where the guest OS window is otherwise. And don’t even bother trying to bring up Ubuntu on the iMac under Parallels on the iMac, but it does work on the MacBook Pro. Isn’t it strange how the supposedly the same operating system works different on the different hardware? Not really."