So, it’s Ecuador. Good move.
First and foremost, while Ecuador has an extradition treaty with the United States, it covers only murder, rape, piracy (as in, of actual physical seagoing vessels), mutiny, burglary, robbery, forgery, and embezzlement of public property. A supplemental treaty (scroll down to page 5 at the link) added other crimes, but not espionage or treason. Moreover, Article 3 explicitly states, “The stipulations of this treaty shall not be applicable to crimes of a political character.”
Second, President Correa is already on-record as supporting Julian Assange. In theory, if the U.S. really wanted to, it could squeeze Ecuador’s economy until the pips squeak. (Ecuador refines most of its consumption of fuel in the United States.) In practice, that isn’t going to happen. Ecuador would likely resist, the attempt would generate outrage across Latin America (and be of dubious legality) and at best the U.S. would simply get custody of a man who no longer poses any national security threat.
Finally, he can get a pretty good quality-of-life. Cuba is ... well, Cuba. Venezuela has out-of-control crime, an economy careening towards collapse, and a burgeoning political crisis. Ecuador has none of the above. There is some (weak) doubt about the recent decline in the homicide rate, but in general crime is, if not quite low, then well within the American experience and not something that would seriously affect day-to-day life. President Correa looks pretty secure and has not generated the kind of opposition that would throw Snowden to the United States just to tweak their Bolivarian predecessor. Finally, the economy is doing okay ... besides which I suspect that Snowden will find some way to monetize his notoriety.
Like I said, smart move.