Berlitz is definitely not a nice place to work for.
1. The hours that you work are "normal" but due to it being scheduled for different times of the day, it leads you to being at work or travelling between home and work 6am to 9pm on most days. That was terrible especially since you still have to prepare for the next morning when you get home at 10pm! And preparation for classes will take you up to 3 hours, especially when you are new to the programme.
2. They are strict about the smallest things and will give you official warnings for the smallest things. They gave an American warning an official warning after he arrived late to a place to give class that he has never been to in his life (got lost) and after having been in Bogota for only less than a month! This makes you feel very unwelcome and unsure about your future there, especially if you a non Colombian mentality of taking these warnings seriously.
3. The pay is less than average at best. You can earn much more teaching at most "real" children's schools and get fixed hours and much more holidays.
I definitely don't recommend them. They have a good name but in reality it is a really bad place to work for.