Fast question: What about sunpower?
On Ebay there are good condition used panels with prices nearly like chinese panels, and Sunpower life span it's much higher (Sunpower said).
https://www.ebay.com/p/10pcs-of-SunP...d=263946836816
If sunpower last 3 times more (much less efficience degradation each year), the price in this sense it's reduced, but this for very long time consideration (a life maybe) and in 60 year something much better would have come out.
But used models in good shape are atractive in prices.
Here on Brazil people sell used things for high price, some people even try to fool other placing the price of a new, while on USA they give very nice prices for fast salles.