The chances of postdoc position higher in PhD country
In my surroundings (Germany, Switzerland), normally it's not a problem to get the first postdoc after you get a PhD in the same country. 

However, a PhD in some country that is (sometimes wrongly) believed to have an inferior level of scientific merit may actually block the further scientific degree carrier abroad: impossible to start PhD studies a second time ("already has PhD"), and impossible to get a postdoctoral position as well ("bad PhD"). 

As a result, it is important to weigh the situation and think where and how to earn the PhD degree. I know people who have dropped basically complete PhD works right before defence just to be able to restart in another country.