Vantaggi
The "world's largest environmental consultancy" has grown over the years greenwashing major infrastructure projects. You are exposed to some interesting projects in remote locales. If you can get a contract paying you to do something, management will let you do it. And if you speak the language of this niche of industry, you will be surrounded by like-minded people.
Svantaggi
ERM is built on a magic formula of extremely high billability and sales goals that cannot actually work at the staff level unless you work in a specialized market niche that's humming along. It's a shell game that you cannot win unless you are the ones moving the shells. A lot of the negative comments here about ERM originate in this hall of mirrors. If you want to work in this industry and cannot find another job, work at ERM until you can find employment elsewhere.