MongoDB 2.8 (in RC4 right now, due out "in early January" last I heard) has the WiredTiger storage engine, and as well as high performance and compression also gets document level locking and multi document transactions. The roadmap says this'll become the default storage engine in 3.0 (3rd quarter 2015). I think the blog author's claim that for basically those omissions "MongoDB can still beat TokuMX on a future release. But only in a future release. Today it can’t." observation is only true if you ignore the development releases completely, and will be incorrect within a week or two.
Sure, if you want SQL or traditional relational database, a traditional relational SQL database is a better choice. Using Postgres or Oracle for workloads better suited to tied hashes or BerkleyDB doesn't automatically become "right" though.