Looks like max 50GS/s per their site. That also looks reasonable with the screenshot they have in the article showing 1ns / div horiz. But clarity on the data would be lovely. =)
Also, the 50GS/s is actually more like 25GS/s as it has a Nyquist frequency of 12.5 GHz. This is because they take 2 samples at the same time, instead of 180 degrees out of phase. I wish they had made that clearer to customers, it felt misleading to some.