Pros
For an organization of its size in international health, CHAI is relatively unique: it's very focused on results (and that's not just lip service) and avoids a lot of the bureaucracy of other large global health NGOs (partly because it doesn't take USG funding). If you work on most global teams or most country offices you'll probably feel like you're having a huge impact, especially relative to your seniority. Teams have a lot of variation so ask people who know that team before you join. CHAI is a fantastic place to work early in a global health career, as you'll get thrown into things. The workaholic, high-travel culture may be getting somewhat better over time, and some teams are pockets of sanity in the maelstrom. If you're young, don't have children, and want to work in global health but have limited experience, CHAI can be a great place to cut your teeth. You can plan to work hard for a few years, travel too much, burn through some relationships, and come out on the other side with experience and skills that make you very employable, and more likely to have a big health impact at another organization.
Cons
Pay and benefits are not competitive, especially for internationally based positions, which seems to be an intentional choice by senior management to not be like big USAID contractors. This also means the employee base is strongly biased towards young, affluent, short-term hotshots. If what is really needed is a young consultant or recent MPH grad to do Excel and powerpoint for a Ministry of Health, CHAI will almost always have a bigger impact for a dollar of donor money. If what is needed is someone with more specific technical skills, or more experience (or wisdom), CHAI falls short. This also means employees with substantial debt, with children, or with life priorities other than 80 hour work weeks with absurd amounts of travel will not last long. The CEO is demotivating: I heard him speak to groups of employees at least twice where he opened with "I do not care about your professional development". He means it too, and his priority on short-term health impact over nurturing employee professional growth is a major root cause for high turnover. That turnover ends up hurting CHAI's impact in the longer term, as they have to constantly replace staff who leave for other (more stable) organizations with a fresh crop of young people who will repeat the same mistakes and ultimately result in a weaker, less-impactful organization than one that cared a bit more about its employees and kept them longer.