I have done BRU-SYD last year and BRU-MEL in September. Etihad is wonderful for Y: good seats, great legroom (if you put your legs under the seat in front of you you have a lot of space).

IFE is good except that the comedy series are a bunch of "How I met your mother" and not much more.

Food: 3 choices for main meal, unlimited drinks, you can go to the galley. Coffee is ok.

Overall ambience: nice plane, moodlighting during the night

Abu Dhabi transit: excellent: Arriving in Terminal 1 and leaving terminal 3 but that is not so bad. I used the Al-Dhabi pay lounge ($ 50) which was very good: buffet, good bar, very corteous staff (I asked for a British newspaper. They did not have it but they went outside to get it for me). On the way back I was silver guest so I got to use the Al Reem lounge for free which was not as good as Al Dhabi (one shower as opposed to three).

Seats: while in transit in AD I saw that my seat on the AUH-MEL leg would be in the middle, I went to the transfer desk and they promptly changed my seat to a bulkhead seat. BRU-AUH in a330, AUH-MEL and AUH-SYD in a340.

Melbourne: checkin line was long. My flight was at 11 pm but at 7pm there was already a long line while checkin opened only at 8pm. As Silver guest I had access to The Air New Zealand (Etihad's partner in MEL) lounge which was a bit bland: only cold food buffet, quite dark, everything self service as opposed to in AUH. But is was a good start to the 14 hour flight. Silver gave me as well overweight of 10 kilo allowance and my luggage got a priority tag which was very nice in Brussels, no wait at all. I was offered a paid upgrade but unfortunately I had to decline (Australia was expensive enough)

Luggage: If you sign up for Etihad guest you are entitled to overweight of 5 kilo (standard tier so you do not have to have any status). In BRU, checkin staff did not know about this and wanted me to pay (I left some luggage with my parents so I did not have overweight). Print out the rules from Etihad guest website and take them with you to the airport to avoid discussions.

Cabin crew: very friendly. I got sick on AUH-MEL and they helped me a lot. When returning AUH-BRU staff recognized me and treated me very well. Also, AUH-BRU was not full so I asked to change seats and I got a whole exit-row for me alone :-)