It also depends on where you want to work. I considered doing the Airbus rating, but considering I preferably want to work in northern europe (Scandinavia, UK) I made a 180 and turned to the boeing, mainly as there are more boeings than airbus'es in northern europe. However if you want to work in mainland europe go for the airbus..
One last thing, I have been told that pilots going onto Airbus'es as their only jet-type typically have problems later transitioning to boeing' as they now lack basic skills required to fly an aircraft as we know it... "non-airbus"..
A course you may look into is the jetlink.lu course, it will give you the A320 rating (Sabena flight training) as well as 500h on type (Adria airways/Air Arabia). I went for selection for this course and found it to be a serious course worth considering if you have the cash..