Hello Everyone.

It is 2 months since I have started mining ( 30 pcs of M3 ), now I am planning to add more 15 miners I narrowed down my choices regarding to my circumstances and result is: s9j or Avalon 851.

now I had some questions I will  be happy if u can help me about their quality and  performance ? ( without considering cost of electricity and miners price - I have done it my self just need some technical info )

1) which one of mentioned miners is more durable and reliable technically with less break down probability ? (I heard that s9 after few months face some problems like drop in the hashrate )

2) If you have used any of them please share your own experience ?

3) generally which one do u suggest and why ?