What's faster, SELECT DISTINCT or GROUP BY in MySQL?

If I have a table CREATE TABLE users ( id int(10) unsigned NOT NULL auto_increment, name varchar(255) NOT NULL, profession varchar(255) NOT NULL, employer varchar(255) NOT NULL, PRIMARY KEY (id) ) and I want to get all unique values of `profession` field, what would be faster (or recommended): SELECT DISTINCT u.profession FROM users u or SELECT u.profession FROM users u GROUP BY u.profession ?