Use properties files as a save/load FILE

hey guys,
im implementing save/load in my game, but there are so many ways, im looking for an easy one, we can use XML, text files, Serialized objects, properties files,

i personally consider using property files, i think is the easy way,
but i want to know whats the best aproach to do that, for all kinds of games, scrollers, cenital RPG, platforms?