Pros
Some highly successful and enjoyable teams in a couple regions; hope you end up there. Nationwide offices and regularly getting new work --> opportunities for advancement and relocation. Supportive of career development, certification pursuit, conference attendance.
Cons
Strict about compensation adjustment, so if you start below a level you feel appropriate, expect to remain that way throughout your time with company. Growth focuses more on acquiring new companies than organic growth, so merging/integration are a constant theme and time drain. Difficult to maintain consistent company culture and strategy. If you aren't in one of the more successful offices, you'll find teams who don't seem to understand the changing nature of energy efficiency programs and utility needs, may spend all your time playing catch-up or protecting existing work instead of trying to get ahead. Often long hours 3-6 months out of the year, as many full-time employees spend up to 40% of time doing BD work to win new contracts. When finances get tight, the first thing to go is necessary program support or employee bonuses, rather than corporate profits - - leads to very poor general atmosphere in times of slower growth or not winning contracts.