Interesting statistics. I have had an array of 100 cheapo chinese tubes for about 8 years and I am happy with it. I have had 2 tubes "fail". These have not lost their vacuum, but the dark covering on the metalwork within the tube has disappeared. I suspect this happened when the system overheated during a power outage (so no circulation). I bought some spare tubes when I bought the panels, so replacing the faulty tubes has not been a problem.
From the figures I have seen there is no great difference in the performance of flat panels v tubes, and either would work for most people. I selected tubes for ease of installation. A tube system is installed piece by piece whereas a panel is indivisible and must be installed in one hit. I didn't fancy manhandling a large panel at height up a ladder on my own. Much easier to carry one tube at a time.
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