Pros
Traveling, as much overtime as you desire, ability to plan your days (if you know you can do the install fast, you can show up to customer sites later in the day), company vehicle with paid for gas from the company, per diem allowance for food and hotels, ability to work on heavy equipment and trucks (cool imo).
Cons
Subpar working conditions, long working days, labor that is hard on your body, gone from home a lot, have to buy and supply your own tools, dealing with rude customers(rarely happens though).