Pros
ARM is the leader in its space, which is the design of low-power chip architectures. (Always work for #1 if you can!) It also has an exciting new IoT business unit. It was consistently profitable while a public company and was recently acquired by Softbank for $32B, so it continues to have a supportive corporate parent with deep pockets. The CEO Simon Segars is a decent human being (unlike so many hi-tech execs!) and is also an excellent manager. Companies tend to reflect their CEOs, and ARM is no exception. ARM has a healthy, rationally-managed, evidence-based corporate culture. Even people who are very busy always find ways to make time to answer questions and meeting or talk with you by phone if needed. I'm really happy here! Benefits are excellent as well, and comp is competitive. If you want the exciting feel of the startup without having to worry that the company will go under in 18 months or be run into the ground by crazy managers, ARM's the place for you! ARM also provides people the opportunity to move between roles and grow in their career.
Cons
It's a fully global company with HQ in Cambridge, major development centers in Finland and Israel and Austin and Shanghai, a US HQ in San Jose, and sales offices in East Asia, so expect some conference calls at odd hours from time to time.