Pros
They make some really cool toys. The campus is great. There are some really smart people to work and play with at Apple.
Cons
Apple corporate memory is very spotty at best strewn across emails and bug reports and the occassional standalone blog. It is very difficult to come up to speed. Information is also highly restricted by project rather than cross-functional which makes work difficult and design from foresight very difficult. Every part of the entire software stack is modified at once throughout a new OS product / version cycle including dev tools. QA is much, much too sparse and Apple depends on all devs eating the dog food while trying to meet their own very aggressive schedules. In the groups I experienced their is very little real design except in the heads of individual engineers. Their software stack sucks. Objective C is archaic and long of tooth as a dev environment. Every developer regardless of seniority and experience is expected to sling fixed bugs (radars) at a certain rate to be seen as worth keeping around. Everyone has to prove they are a good Apple drone before they can do anything creative. And/or they have to work nights and weekends (if they don't already have to to even keep up) to do something that gets them beyond drone mode and have some measure of control over their time and destiny. The people that make it seem to all work 60 hours or more a week.