Big, if true. But do keep in mind that discoveries like these are often overestimated at first in order to drum up sensationalism and get attention for the people that discovered it, with later estimates tending to significantly reduce the size estimates.
Although, since we're already on the topic, if anyone has not yet seen this, it's also pretty cool:http://www.bbc.com/news/science-environment-38224564
I'm honestly surprised at how little attention this has gotten. It's an actual dinosaur tail in amber. Not a fossil, the real deal.