From EZE
Our flight from EZE to Lima and SJO left at 7:10am. With driver arriving at hotel early, we got to EZE a few minutes past 4am. No lines. Boarding pass, tax counter, security and immigration took total of about 20 min. So lots of dead time drinking coffee in gate area. (I did notice about an hour later lines in secuity were much longer.)
PS. In SJO there is a brand, new VIP lounge. But no airline members. They have some banks sponsering. They hope to get TACA or AA to add as a club, but not yet. They charge $35 to enter - with bar, internet, some sandwiches (I think), and nice couches and A/C. Looked very nice, but I did not pay to use. It is behind the bottom of stairway - near the smoking bar and the best restrooms in the airport.