I've owned 3 different models of iPhone and the premium support (if you pay it) is worth the price, aside from the issue of booking a time I always leave the apple store with my device fixed or replaced, I never have to come back another day and they always take my complaint very seriously (even showing me diagnostics indicating potential other issues I had not noticed).

I cannot fault Apple's customer service at all, in fact, it's why I still buy their phones instead of going through the impressive hoops I used to go through with sony-ericsson and nokia phones.