I worked for a small company that was purchased by Otis. Eventually Otis lost most contracts, and all the employees that came with the independent they purchased. It is very different at big company vs. small company. That being said, I have worked other big elevator companies, and am grateful for the experience I got at each. They is no right or wrong, just different opportunities. I would be most concerned about how well your local Otis branch is managed, and they reputation they have with employees and customers.