Pros
ASEF is a unique organisation, and working for it is also a rather unique experience. Being apolitical but working with governments brings its own challenges as well as opportunities. While bureaucracy is definitely there and could (as well as should) be diminished, overall ASEF offers their employees a great level of liberty and responsibility to take ownership of the projects they run. The team is small, so each staff member has to step up in order for the organisation as a whole to continue evolving and improving (i.e. if you're just looking for any 9-5 job to put bread on the table without an actual interest in ASEF's vision and mission, this is most probably not for you). And yes, you will most probably end up working a lot. But yes, you will also be inspired and gratified by the work itself, your colleagues, your partners, your participants and other stakeholders. Only you can assess if the significant efforts you will need to put in are worth your time and dedication. If you believe it is, please give it a try.
Kontras
Your experience at ASEF can be very different depending on in which department you work. None is better than the other, each one has its own strengths and weaknesses. The collaboration between departments is not the strongest, but you can yourself influence this, if it's something that is important to you. Unfortunately Asian and European governments are not giving ASEF or the ASEM Process sufficient support (political, financial, human resources, etc.) which can lead to some challenges in relation to implementing projects. Expect hence having to come up with creative solutions to these and other challenges related to the characteristics of the organisation and its work. While interpersonal conflicts have existed in the past, the situation has improved the past couple of years. Such conflicts can come up again though at any time (and in any organisation/company), so it is also your responsibility to contribute (and avoid being counter-productive) to a healthy work environment, if you get such an opportunity.