Pros
In a consolidating industry, ASE is doing well. It has some natural advantages because its top management understands real estate and has strong government connection in Taiwan and China. Top management is capable. Job is stable.
Cons
(1) Pay is low. Long hours. Add these two together, pay is even lower. (2) Much of the company's direction is driven by the sales organization. The sales teams are driven by short-term performance. A lot of sucking-up to customers. A lot of finger-pointing if quota is missed. (3) Middle management is weak. They have two modes of operation: ignoring you (if customers don't complain) and micromanaging the poop out of you (if customers complain). (4) Limited career advancement. If you don't speak some kind of Asian languages, especially Taiwanese and Mandarin, don't expect to advance much. Since most people you deal with speak English poorly, communicating in English is actually a disadvantage. (5) Lack of IT infrastructure. There is a ton of paper work, think sales forecast, sales report, travel expense, product spec, etc. They make you do them manually. The management refuses to improve your productivity by spending on IT, so you are stuck performing low-skill, long-hour tasks.