Depends on the status of that person. The Ottomans hired/employed various westerner's (usually Venetians) to keep fleets and attached weaponry up to date with the rest of the West; These people could do quite well for themselves although if you were a christian orthodox peasant living in the Balkans life would be quite hard at time depending on how the empire was doing as a whole. Taxation was collected/enforced by a local lord or Governor under the Timar system which was in effect an autocracy, this individual being second to the sultan himself. Depending on the greed of the Timariot, you could be taxed at varying levels with the Timariot taking a cut off the top which didn't bode well for your average peasant in the Balkans/Greece during times of drought and famine.

This is not to mention the Devshirme, the muster that occurred every 4 years in which some christian children were selected and then taken away from their parents to be raised as Muslims with the idea being that they had no family, no nation and that their only allegiance would be to Islam (and thus the Sultan). Generally speaking however these converts went on to either attain high level positions within the bureaucracy or Janissaries in the Sultan's army.

Basically if you didn't tread on any toes and paid your taxes you didn't much get bothered although you were very much at the mercy of the temperament of the local soldiery and Governor.

Source: Why the west has won by Victor Davis Hansen