As someone who has worked in young, small and medium, old and larger companies: I wouldn't use mongo/couch outside of non-critical webapps even if I was paid to do so and for my own (cynic) understanding, it is as much a "database" as a folder with clear text files is.

Yes, Oracle is big, bad and "ebil" and I cannot stand their sales drones.. but if you ever had an "oh CRAP" moment, chances are very good that the db has got your back. Of course it also has its downsides like any other huge software product...