RX 580 I like more but I don't recommend you to buy these GPU second hand. You don't know how they worked in the mining business. They can be overheated. They certainly require replacement of thermal paste. On this equipment there is no guarantee. The payback period of these GPU 7-10 months. It seems to me that you can not pay back. It is better to buy a new one.
Saphire have better fan than MSI. and agree with you about buying new one (due to Mod bios...) except if 2nd hand are still under guarantee.
Just found 1 2nd hand Saphir RX 570 for less than 150 euro with 1.5 year guarantee.