Used the GB 7 times.
The more iniformed I acted the better the results were.
Exactly.
Early on in my MacbookPro's life, the DVD drive started acting badly. I did a lot of diagnostics at home, including creating a new account on the machine and bringing in some sample DVDs that didn't work.
I was able to relay all this info to the "Genius" and he said, "you've obviously done a good job diagnosing - I'm not going to even bother testing." I left the machine and he quoted 2 days (no charge) and I asked him to try and get it done sooner. This was all at about midnight in the Fifth Avenue (Manhattan) store. When I turned my phone on the next morning, I already had a phone message that the machine was ready.
When I got my iPhone 3G, battery life was very poor. I brought it in and they ran a quick diagnostic. The diagnostic did report back something negative, but not a battery issue. But the tech said, "I don't really see anything wrong, but I'll replace it anyway". And the new phone did turn out to be much better.
Years ago, my daughter had an infant and her laptop on her lap and the infant pushed the screen back and broke the hinge. The machine still worked for a while if they put a book or brick behind the screen. But then the video stopped working. She brought it in and they told her it wasn't worth fixing the screen because it would cost $1500, but she had them fix the video. She got the machine back and they fixed the entire thing, including the screen, presumably by mounting the whole thing in a new case. No charge for anything. You can't ask for better customer service than that. Maybe Apple lost some $$$ on that repair, but they gained a customer for life (more than one, actually).
More recently, I went in to buy the new phone, which I didn't wind up getting because AT&T signup was down, but the sales person I was dealing with didn't know much of anything (but this wasn't someone from the "genius" bar.) He didn't even know that most business users use Exchange and Outlook for email.
I'm sure there is some variance in how qualified the geniuses are and therefore, people have had different experiences, but I suspect someone who simply says, "I hate the genius bar" has probably walked in with a hostile attitude and got bad service as a result. One thing to keep in mind though is that even though Apple tends to pay slightly better than most retail, a "genius" generally makes a small fraction of what someone who supports Macs in a corporation makes, especially if they're also supporting the network. So if the corporate jobs are available, Apple isn't necessarily going to attract the best people, although I'm sure there are many people who prefer working in retail to working in a corporation.