Pros
good pay if you don't mind being pushy and selling a lot of units and IAQ upgrades. stable job because of the size of the company, you know they are not going to go out of business or lay off during the slow periods. you will have work during slow times of year because they do LOTS of maintenance, i do probably 25-30 maintenance calls a week, and run only 5 service calls a week average. lots of training opportunities, very safety focused.
Cons
opportunity to advance is only likely if you move. if your branch manager leaves and you have already been training for years is the only way you will get lucky and move up within your branch. after that, plan to move if you advance any further. branch manager is as high as it gets at branch level unless you are at a main branch in your area. usually the area manager already has a pet who will be first in line for the branch manager openings anyway... to make really good money you have to lose your self respect and sell sell sell, new units, uv lights, filters, humidifiers, etc, for the commission. you're constantly ranked by how many leads you set, how many uv lights you've sold that week, etc. it's how you're graded as a technician, and how you're evaluated for advancement.