PSI is a NGO set up. It is definitely safe place for women to work in and many women with children work in this organization.
However since it is grassroots level NGO you may have fieldwork and should be comfortable working with poor people and going to slum areas if required.
The cons are 6 working days and the pros are you will get empowered in the process not met any PSIan who has not transformed into empowered folks.
It's a women friendly place. They respect women and give importance to their inputs and suggestions in the work place. Pay will be good. As regarding to cons, rules are rules for everyone and one need to equally work to that of a male employee. But they do consider family constraints or issues..
On Pros and Cons, They used to have good leadership picked from the best of PriceWaterHouse Coopers, but projects used to be a little directionless and we often found ourselves struggling to find big picture objectives. The firm was unclear about whether to pursue pure IT application building or build in management consulting services as well. This confusion percolated down to our teams and would often result in employee as well as client dissatisfaction.