Pluspunten
It is a very engaging environment, where you can meet a lot of people from all around the world. It can be demanding sometimes, but it is still a scientific environment. You normally have full control over your workday, as long as you do your job, you can come and go whenever you want (generally).
Minpunten
Even though the organization seems to be at the forefront of science (which is clearly the case in high-energy physics), in other areas it is still stuck in the 80's (namely engineering and IT partly). In addition if your job is not being a particle physicist, you most likely are only the support structure (engineering/IT) for them. With its up to 10000 members it is also as static and immovable as a big company. There might be actually at any time 2-3 persons doing the same job/research without knowing each other... Career opportunities are quiet rare. It is easy to be a technical student (1 year contract), a PhD student (3 years) or a fellow (2-3 years contract). Unfortunately actually getting a staff position is already an accomplishment. Furthermore the staff contracts are limited to 5 years and there is maybe a 30% chance to get an indefinite contract for life. When it comes to life in the area, it is very expensive and can be quiet boring, if you are not interest in hiking and/or skiing. But the view is quite astonishing. Geneva is very much a train station city, a lot of influx of people and in general, due to the short contracts of CERN and the UN, you might say goodbye to around 15 friends you made per year...