I am a student in the current cohort at Zipfian, and I would have to agree with you to some extent. I did a M.S. in statistics and everyone who has interviewed me so far still considers that to be the most important qualification.
However, Zipfian has helped me get familiar with a lot of things very quickly--pandas, sklearn, MapReduce, Pig, Hive, SQL. They have some very, very good "sprints" (long exercises) and they just generally keep you on track for interviews and force you to do very useful technique things that you wouldn't be motivated enough to do on your own, or that you wouldn't know about. Some of things might not be useful for interviews, but they might actually useful on the job, especially at a startup.
