I cringe every time I read that. MySQL replication is many things, but it is not reliable (as anyone who has used it at scale will confirm).
I think the only reason this myth prevails is because hardly anyone ever actually verifies if their master/slave are in sync. A table checksum can be a real eye-opener here, especially on a deployment that's been running for while and undergone schema changes, restarts, network splits, etc.
PostgreSQL's built-in replication is pretty easy to set up[1] and provides a writable master, and a cascade of slaves. Slaves can be synchronous or asynchronous, and the synchronicity can be turned off per transaction.
[1] http://www.depesz.com/2011/01/24/waiting-for-9-1-pg_baseback...