I don't think emirates is cheaper than etihad for flights out of UAE, although obviously they have a bigger network.
Depending on where you are going to for holidays, I like to book a redemption flight to bkk or kul and after a few days there take a low cost carrier from that region to an onwards destination. Srilankan airlines, Flies out of AUH also with low j class fares to Asian destinations via Colombo which can include a layover in Sri Lanka, which is a must!
Both ADCB and ADIB offer credit cards with great earning rates, I find ADCB to be the more user friendly of the two.