Pros
I've worked for this company for over 5 years. Originally it was just a stepping stone until I found another job that I really liked. However, as a whole ESS takes the time to listen to their employees in the field. They are reasonable with their expectations. The work is challenging and keeps you busy. They respect you and recognize your personal accomplishments. Pay is decent for what we are expected to do. They want to develop and promote as many employees as possible, so its a great launching pad for your career. Great hours, decent benefits, good management. Great place to work!
Cons
Most Saturdays are required. As a large company they can be fairly strict on certain things. There are slow periods in the winter, sometimes. With generally only two employees working per site or if there is someone that leaves ESS, your schedule is sometimes difficult to have exactly want you want off; this is uncommon though.