Pros
One of the best reasons to work with the Student Conservation Association is the quality of the people who both work there and apply to work there. It brings together people of all ages with a desire to work in the environmental field without being too restrictive based on experience - they are the best way to develop your background in environmental work, and they'll help you find your dream job along the way.
Cons
The only problem that I have with the SCA is also one of the reasons why they are able to be so great at what they do - turnover is high, as with most positions in the environmental field, because the bulk of the jobs they offer are low-paying. Since they are largely taxpayer-funded but have an ever-growing demand for work, they need people willing to do fun, exciting work for little.