One of the things that I think puts people off from CouchDB is the comparative complicatedness of the query system, what with having to map/reduce and all. SQL

One of the things that I think puts people off from CouchDB is the comparative complicatedness of the query system, what with having to map/reduce and all. SQL queries are incredibly flexible by comparison, not to mention that SQL queries are how many developers think. But after studying data structures, I realized that most other databases have a lot of time complexity involved that they are basically sweeping under the rug, whereas Couch's relatively simple query model can guarantee that it's roughly O(log(M) + N).