They're complementary. The ODS system mentioned there is more for monitoring numerical metrics (like Graphite) and doesn't support logging arbitrary data.
ODS is good for top-line metrics and can handle more volume but doesn't compare to Scuba if you want to dig in and look at individual rows in your data (or even just analyze your data and group based on certain columns).
For those who don't know, the Gorilla database is also from Facebook and they published a paper about it roughly a year ago: http://www.vldb.org/pvldb/vol8/p1816-teller.pdf