Pros
Excellent compensation and benefits. Professional work environment that values motivated individuals with a strong work ethic. Understanding and supportive management in all respects with a willingness to allow you the time needed for anything personal, no questions asked. Excellent training programs for equipment. Opportunity for advancement and (compensated) relocation.
Cons
Incredibly dangerous work with every type of potential hazard you can possibly think of. Ionizing radiation, corrosive and/or toxic gasses, high voltage, small cramped spaces with limited air and potential mechanical hazards, fire hazards, etc. Lots of travel for extended periods of time, especially for initial training. This can be a positive if you don't have a family. I enjoyed the opportunity to travel all over the world, but after 6 weeks in a country where I cannot communicate with most people because of language barrier I was incredibly homesick and missing my family.