Pluspunten
Relaxed work environment, great benefits. All technical full-time employees get a private office with a door, barring severe temporary overcrowding anyway. Very family-friendly atmosphere, with a lot of flexibility in terms of normal work hours and time off for appointments, etc. No set number of sick days - if you are a child/parent are sick and need your care, you don't come in to work.
Minpunten
It can be difficult to get new ideas rolling. There's a lot of political interplay and infighting at the middle management level at times. It takes persistence (and a great demo) to get anything to happen sometimes. Low turnover is a sign of a great company to work for, but it also means that opportunities for advancement can be limited.