Pros
In general, really good day to day colleagues- worker bee level includes smart people who really do care. Certain departments are well run. Decent work life balance. I appreciate the move in the last 5 or so years to establishing things like pay bands- though promotions are still very subjectively awarded.
Cons
At the end, I found the Executive Management Team to be ineffectual and pretty toxic. After Tetra Tech bought MSI, MSI slowly lost its culture- what made it different from other big contractors is gone at this point. It's all about winning awards. Tetra Tech is all about shareholders and profit. The staff benefits have been reduced following the TT acquisition, salaries are lower than many of the competitors and benefits are not on par, and as you move up in rank, the inefficient hoop jumping and day to day changing authorities increase. I do not believe in the management team at all at this point.