Pros
Balance between technical engineering type work and big picture regulation work. Good career advancement. Some employees (like myself) have outside industry experience and expertise. Industry takes you seriously and listens. You get to know some of the most experienced people in industry. Great benefits and the pay is not on the GS system, so you are generally paid more competitively towards industry rates. Life balance is good.
Kontras
As an engineer you are not going to be doing design work. However, you are involved in the design and testing and ensuring designs meet safety requirements for a broad range of systems. Some bureaucracy, but if you are used to other fed agencies, this one is actually pretty efficient--mainly because they have the ability to bring in good people with the competitive salary scale. Can get busy, but still a fed job with fed job hours (quite fair).