I have worked in both Ireland and Germany [and Switzerland, UK, Belgium, Middle East etc etc].
Those thinking of going to Shannon - nice centre, sh*t load of traffic onto and off the North Atlantic, makes Australian sectors seem tame - BUT you need to live in Ireland, and it can be pricy [read dollar for Euro - i.e. if something costs a dollar here, it would be a Euro there] and the tax regime is not as 'user friendly' as here. Cost of living is a little higher all round [fuel is horendously expensive!] - AND you need to learn to drink - the guys at Shannon centre can drink!!
Those thinking of going to Germany - particulary if you go to Frankfurt or Karlsruhe - traffic again is VERY heavy, and VERY constant, but rewarding. Military traffic is a PITA. You will need some German - and will need to be fluent to work on certain domestic sectors - GA are allowed to speak German in domestic airspace. Cost of living in Germany is like Ireland - dollar for Euro. Bureaucracy is hard to work out at first - but not impossible.
Better option than Germany might be Eurocontrol at Maastricht - but you'd need a link to one of the member States to get a job - unless you backdoor it by going to a non-operational position first - work for a year, then go in as a Eurocontrol employee.
UK also has some private airport options if you are tower and/or approach rated. Problem is there is a catch-22 - you need to have UK endorsements - but you can't get them unless you work there - and you can't work there without them! Again there is a backdoor - see if you can find an airport that is willing to sponsor you through a short-term [8 week] training course. You could also go direct to the several training orgs, but you'd need to pay for the course yourself. UK living costs outside London are high - in London are prohibitive.
Switzerland does take Oz ATCs into ops support roles. To work operational at Zurich you need GOOD German. To work at Geneve you need EXCELLENT French. there are a few summer only tower jobs - you'd be bored sh*tless in a week.
In short - if you want to leave Oz and work as a controller, and you want to put a few dollars in your pocket - go the Muddle East options. If you really want the lifestyle change, to experience life in Ireland, or Germany, be prepared to come home a little poorer in cash [but richer in memories!!!].