Pros
Terracon takes safety extremely seriously - rank-and-file and management are truly beginning to incorporate safe work practices and critical thinking. The unusual thing: the rules are being driven by a desire for safety, not for the sake of rules. There's been a big emphasis on conversation/coaching vs. monitoring/punishment. The people are the other best reason to be here. Office has less than the usual number of bad apples. Everyone gets along really well, and there is a definite teamwork atmosphere. Terracon has geotechnical, materials, environmental, and facilities service lines. There is staggering potential for cross-selling and cooperation between the service lines in the bigger offices (Houston, Dallas, etc.). Environmental and Facilities will learn a lot of different things; Geotechnical and Materials will be working to engineers who have a lot of knowledge to pass on.
Cons
Average pay; fast-paced consulting work leaves you at the mercy of the client; sometimes management won't stand up to client demands, leaving you with yet another 60-hour work week you won't be getting overtime for. Great place to start for engineers fresh out of college; solid pay for older, more experienced engineers; difficult for middle-experience engineers (4-10 years) to do the grind. Hard to justify forgoing a more competitive salary at another firm for ten or fifteen years while grinding to become a principal and finally make serious money with company stock. Mentoring is also ad hoc if you're not a geotechnical or materials engineer. Sometimes you're lucky and someone above you has the background and inclination to educate you on the finer points of being an engineer. Terracon has a reputation as something of a meat-grinder with regards to personnel; it's getting better, but there is some of that mentality still.