For all the positives, it can be an incredibly frustrating place to work, too. Most obviously, but least importantly, some of the customer interactions can be intimidating, and scares off some people from the job. Actually, this didn't bother me so much -- when a customer is agitated, it's rarely *you* they have a problem with, so much as their frustration with the company as a whole and the product specifically. Focusing on the specific problems & needs usually quickly gets you past such customer frustrations, allowing you to come to a resolution to the problem that brought them in to begin with. That's fine, and you either get used to it immediately, or customer service isn't your best line of work.
The bigger frustrations all had to do with the company itself.
Lots of specialists try to get promoted to Mac Genius (or Creative), but there really isn't any credible way for most Geniuses to move up with a technical role within the company, other than to try for a rare job at corporate offices in California or Texas.
The company's secrecy is pervasive, and all information comes down from On High -- you often have a dim idea of where your own store is headed, nevermind the company as a whole. There's little opportunity for good ideas to trickle up from the ranks, or for peers to collaborate with each other across the chain -- rather, marching orders come down from the top and everyone expected to get on board.
For a technology company, they're startlingly reluctant to "eat their own dogfood" -- you often end up being officially instructed to do things in a "sneaker net" kind of low-tech, labor-intensive way when some of the company's own products could have potentially been making aspects of the job much easier.