Often we like to change our browser's skin; say, to fit with some new autumnal theme or have it show icy hills as part of an upcoming Christmas season desktop theme we've installed. Personas+ is simply perfect. It is extremely easy to use. To begin with, go to All, choose the Category that interests you and find one that you like. It opens up in a new tab and the word Undo at the top means that, if you don't like how it looks, you can revert to your previous skin. But what if you don't find what you are looking for? After all, there are thousands upon thousands of skins.
Well, here is where Personas+ excels: Go to All, then choose the category you like (say Nature). At the very bottom you will find an entry 34,578 More from Nature... If you click that entry, you will be taken to a website on a new tab: the Personas Gallery focusing on Nature Personas. You can then try on different skins one by one, or click on the Search box and put your search terms e.g. "snow trees". You will most likely encounter one of my most favourite skin authors too, MaDonna. If so, give her a shout on her website to thank her :)
All in all, an easy-to-use and great app that truly makes your Firefox look unique to suit your mood.