I completed a CELTA at the BSE in 2009 and can recommend it highly and without reservation.
The three tutors were fantastic, very supportive, straight-forward, all committed to helping the students through what is a very intensive month.
Good computer access, nice resource collection. Great location.
You probably know it costs 1500 euros which is not the cheapest, or most expensive, but worth it, especially if you're keen to work in Berlin.
All in all I can't imagine any CELTA being much better (though admittedly I've only done the one...)
Student or Learner