MongoDB adds atomic find and modify
mongodb.org
mongodb.org
Why would I want to lose the power of SQL if I'm not getting anything in return? I thought that "built-in memcached" was what I'd be getting. No?
In this case, MongoDB is a leap ahead of MySQL; Redis is a leap ahead of Memcached. Both solve the core problems very well and include additional freebies (MongoDB's high-performance aggregate functions and Redis' atomic increments and set and list functions).