Two long haul flights back to back - and SYD - Abu Dhabi is a really long one (14 hours in the air) but apart from that - the flight with Etihad could well match my experiences flying around the globe with some of the other "better" carriers (like Emirates, Singapore Airlines or Air New Zealand).
Service: the crew was on both flights friendly, efficient and caring, though they could offer more drinks during the long flights ... I got them, but I had to ask. It would be nice as well if they would voluntarily come up with some other drinks than water ... offer some juice as alternative, even if not directly asked - particualrly the water on the flight from Abu Dhabi tasted terrible.
Catering: They do feed you, but if you fly to get really well fed, than pick another carrier. None of the meals I had on any of the flights was remarkable. One drawback with Etihad - they don't offer a menue (not even online) - i.e. you don't even know what you choose if the crew comes with their typical "chicken or lamb".
Entertainment system: Particullarly on the long leg SYD - AUD the best I ever experienced in economy class (and I do fly a lot). Amazing screens, responsive touch screens and good and rich content. Full marks for that.
Reliability: All my flights have been on time and my luggage arrived always with me. Can't be any better.
Connection for me was good - three ours waiting in Abu Dhabi is ok - and the airport is certainly one of the better ones.
For me a first with Etihad - but based on these experiences would I not hesitate to use them again if the connection and the price are right ... good one!