Greetings, @preparedwombat. It depends on every person's situation, contacts or relatives waiting, etc.
However, historically there have been considerable tensions between colombians and venezuelans. From the independence war and the eventual separation of the Gran Colombia (which gave birth to Venezuela and Colombia as separate countries with Santander on the Colombian side and Bolivar on the Venezuelan side), both peoples have seen each other as potential traitors or enemies.
That tension has had episodes of solidarity and union because of obvious commonalities. But it has been a complicated love-hatred realtionship.
When Colombia was a mess caused by druglords, guerrilla, etc., millions fled to Venezuela and there they prospered and had families. Venezuelans then saw that as an unwanted invasion. Many colombians suffered discrimination and stereotypical labels.
I think that today is paybacktime for Colombians. That would explain some of the crimes that are being committed against Venezuelans.
So, Colombia may be atractive, but at the same time offers many potential complications.
Peru and Argentina because of how far they looked before (obviously they are, but you know what i mean) do not share that history, had not dealt with many venezuelans before; theoretically have nothing against them and shoudl actually thank them for having received them when they were the ones leaving their countries, plus they have offered some advantages in terms of paperwork (less).
Chile did it for some time, but it has started to tighten up. Can't blame any of them. We are talking about an unprecedented migration whose real numbers will take some time and honest counting to determine.