Yes, quality is the most important above all. And I agree with your statement on how an additional core can be an advantage or a disadvantage depending on the application/climate.
Buying an aluminum radiator from far east online is undoubtedly a gamble, but just like any gamble, sometimes you win something too
If I were in a the market for an aluminum radiator, I would probably do my homework and end up purchasing from a reputable, western or far southern based manufacturer and pay the difference. But if somehow someone here we're to identify a quality radiator from say Taiwan, I might get one and stress test it.
In my opinion having three passes over one can be very advantageous IF certain other considerations we're to be involved. A deep (thickness) radiator with 1 or 2 cores will allow for high flow, great tubular surface area and structural integrity. And since the coolant is passing three times (at one third of the radiator area at a time), the drop in temperature towards ambient can be realized, even with a slight higher flow rates.
Multiple (generally 3 and up) cores will have the inherited tendency to dump some of the dissipated heat back in the subsequent cores, reducing efficiency. Also, the addition of more cores come at the expense of flow and
net tubular surface area. I know these are not necessarily tremendous issues in our applications but it is a factor especially under high load, low air speeds, and oppressively hot climates. That being said, this heat recapture is one of biggest contributors to loss of efficiency in charged air coolers, particularly in the air-to-air verities.
If one examines the cooling setups of a modern, very high power/extreme duty vehicle such as the ones in rally cars, they will find that large area, single core multi-pass heat exchangers raign supreme.
Small world, I too was in the Sahara in August
Cheers!