My plan to try out its more serious image editing features properly was rather scuppered by them putting some seasonal editing tools out for the Christmas period, though :)
Kudos to picnic for having something that complicated work perfectly in Safari, too. If you give it a go, bear in mind, though, that it can be a bit slow starting up. There are a couple of long gaps with a blank screen (between progress bars) where you might think it's died, but if you persevere, it springs back to life. Once it's working, though, it's fast, considering what it does.