Pros
Turnover is VERY high, so if you can survive, chances are you can be promoted. Organization is well respected from outside, so potentially a good resume builder
Cons
Management more focused on large donors than on members, leading to a few "scrilla gorillas" dictating campaigns and mission. Building support in poorer neighborhoods tends to get lip service only
Management is totally uninterested in stemming the tide of turnover due to burnout and complete lack of work life balance. There is an expectation for a LOT of night and weekend work, with "flex time" the intended trade off. However, there is no way to actually work 40 hours a week average and meet goals, and working so many weekends and evenings means that even with flex time it is very hard to see your family.
The organization is constantly in "fire put out" mode and will not prepare a more stable work environment. The clearest example of this is the CRM. Since there is not enough buy in or staff time devoted to keeping the CRM running well or learning how to use it, people often resort to google docs and excel spreadsheets because it is "faster." This combined with the high turnover means that the institutional memory is slightly longer than that of a goldfish.