Aussie,
As Poland is in the EU, you have right of abode anywhere in the EU. There are places to work where you'll get much better T+Cs than either of these two. If you're looking for hours and a stepping stone, try and get either a 737 or Airbus out of it. I'd be reluctant to cough up any money for any sort of self sponsorship scheme, as neither (and particularly WIZZ) is particularly well financed. You could shell out mega-bucks only to have the company fold before you get anything worthwhile out of them.
As an Aussie, Britain is still probabley a better bet. Can't comment on Turbo-props in Eastern Europe (though there are still a lot of dodgy looking AN 26s hanging around) but a bare frozen ATPL and willingness to pay for a rating gets you looked at by Turbo-prop companies in the UK.