I won't be there for Marathon or Star Wars, but I've got my Princess one ordered already. I don't know if you'll be able to get one at this point - the Princess ones sold fast, I think they were gone inside half an hour - but if you can, I'd go for it! They look cool, and they're pretty unique.
When they first announced them, I wasn't able to see them on the site, but they fixed the issue a few weeks later and I was able to grab one. I assumed we'd pick it up with other preordered stuff at the expo. Any one know if W&D folks got theirs early? That might indicate what they plan for MW.