The lifestyle is pretty good. I am married with no children and there is plenty to do. You find that the majority (not all) new joiners tend to take the allowance from the company and live at Al Reef or Al Bandar. Reef is a family environment and my mates who have wives and kids seem to enjoy it and the wives make friends which keeps them happy. Al bandar is apartments but can be expensive. For example in reef you could get a 3 bed town house with garden for 130k...the company give you 160k. 4 bed is about 150k. Whilst reef is a bit in the middle of nowhere (not far from airport) it is only 50 mins drive to Dubai where you have millions of activities, and it's around 40 mins from Abu dhabi city.
Lifestyle wise Abu dhabi is smaller than Dubai but is getting bigger every day. You find you get discount in most places for food/drink etc. Yas island is pretty cool, they open the formula one track for you to run/cycle...
There's loads of stuff to find if you go out looking for it...have a look at the Time Out Abu Dhabi website, that should help ya
Oh and in terms of time off it depends on the fleet your on...at the mo 777 lots of time off but will change later in year. A320 usually 8-11 days off per month