Pros
If you are lucky, you can get placed on a line that will allow you to learn some testing and troubleshooting techniques to expand your knowledge base. If you keep your head down, you can work there for years and not have to actually do your job.
Cons
Things are generally made up as they go along. Designs are slightly changed after approval. Components for hundreds of units are ordered, deadlines are set, and units are assembled based off of older specifications. The technician's skill or work hours are blamed for the delays, but it's really a design verses testing issue. Project managers aren't technical enough to understand. Engineers are already overwhelmed with designing and redesigning other projects, so they can't be bothered to actual come help. When they do help, it's more of a "Take off part A, test again, and I'll be back in an hour to tell you to try the same with the rest of the alphabet." type of help. Managers will then hold poor planning and their own bad choices against you at annual review. You could be placed alone on a line that you completely handle by yourself for a year, to everyone's surprise, but they'll still ding you because you haven't shown that you can work with a team. You could ask for a promotion, but they'll tell you that you already make close to what the next level gets paid, so what's the use of promoting. Other people could not have actually done any work within their job description for years and will still get promoted. Some job titles are are just made up and the positions don't matter. The company mostly follows the good ol' boys system. If you go to church and/or the gym or are childhood acquainted with upper management, you'll advance extremely quickly from one random title to the next.