Having worked for ZIMEX for a portion of my working life all I can say is that they are a great company to work for. Your colleagues will generally be great people from amazing backgrounds and you will form lifelong friendships with them.
The experiences and often hardships whilst on the posting usually bring out the best in each person and you form a cohesive team and get the job done.
Having worked in both war and peace time projects I have many wonderful memories, and sad ones from those times.