I've flown quite a few times SYD-HNL and vv. in StarClass. I agree that it's more of a premium economy product than business, so that's a good point to base your expectations.
In my experience, the cabin crew provide good friendly service, although I've never tested them with any difficult requests. However, on one occasion, they failed to deal with passengers standing in the aisle and having a conversation so loud that they woke up the whole cabin (including me, and I had earplugs in and was also wearing noise-cancelling headphones); they did respond after I pressed my call button, but I felt that they should have intervened without needing to be asked.
The seats are okay, but nothing special. I found that the PE seats on the QF A380 are better, although not leather. The footrest on *C wasn't much use for me (I'm 6' tall), while I found the PE on QF much better.
The food was okay, but I think it may be the same meals you can pay for down the back, although I think the dessert service (cheesecake, etc.) was just for *C.
IFE are individual digiplayers - not a huge selection, and the units themselves seem quite tired. They come with noise-cancelling headphones, which work, but again aren't fantastic.
The only issues I've encountered have been to do with noisy passengers (see above), and occasional very long delays, although the passengers down the back had the same delay.
(We were 4 hours late leaving Sydney one time, and on other occasions have been 30-60 minutes late.)
For me, the real benefit of *C is as a cheap-ish way of getting SCs, and as a way to get halfway across the Pacific in better-than-economy seating but without paying too much.