I was upgraded from Y to C on the SQ392 to Istanbul a couple of weeks ago.
Had arrived earlier in the evening from Auckland on a long afternoon flight without any sleep, so it was an extremely pleasant surprise when my BP produced a red light and a beep at the gate on boarding my connecting flight.
Needless to say, it was a very comfortable experience with attentive and friendly cabin service.
I-m the kind of *G who travels mainly in economy, so I don-t usually expect more than the standard benefits of premium check-in, lounge access of some kind and priority boarding.