Pros
A great door opener to jobs elsewhere, particularly early on during your career. If you're young and inexperienced, they chuck loads on your shoulders which is good for making you into something. Other than that, it's difficult to find anything which was great about my time at Apple. If you want to work at Apple, make sure it's short and sharp. Use Apple on your CV as a door opener.
Cons
Don't be blinded by the sheer shine of Apple in the UK. As someone on the inside, I've seen a lot of colleagues go through nervous breakdowns, breakups/divorces, strops, bitching, and dismissals for minor things. Apple has very little sense of humour, and its employees frequently overworked and stressed with little support for career progression work life balance. If you work for Apple in the UK it's one of the most uncreative, dull and miserable places to work. In truth, it is more of a call centre with a load of project managers regurgitating the tightly controlled creative from the US for a European audience. I can't vouch for Apple US or (Apple Worldwide/ the 'mothership' as we used to call it), I've heard that over there it's entirely different and lives up to its image. If you're in the UK and are looking for a job with which you can grow and develop inside the company, with friendly people who are happy to help and give you progression don't come here. I've known several over qualified and amazing industry pros who moved to Apple hoping it would be the pinacle of their career (as it should be) and have left 2-3 years later, bitter about the lack of career development in their roles, having committed years of their time to Apple but staying stuck in the same role.