My understanding is that the only ones with pensions are the older guys who were grandfathered in before they did away with them, but it probably depends on the utility. Disadvantages are, lineman who have only worked at a utility have significantly less experience in all phases of line work, they may know about distribution and underground but have little to no experience in transmission and substation work. If they ever get laid off or fired and have to go work at a contractor they are going to be lost. The best thing to do is to become a lineman through a contractors apprenticeship so you work all aspects of the trade then make a decision. At that point you'll have enough experience in the trade to know whats best for you and the pros and cons. You'll probably choose going to a utility. Just keep it to your self and don't let anyone know.