UPS will be delivering my 1st S2 Bitcoin miner from Bitmain. The price had been reduced lately to super low, as low as $1500 for a used one on ebay and amazon, even lower on forums and craigslist.
I have many of the S1 model of Bitmain also, but those S1 uses a lot of power and can only mine at 200gh/s each, and 1000watts PSU can handle 2 S1 total of 400gh/s while the S1 also uses 1000watts but can mine at 1TH/s which is more than twice the speed of the S1. The S2 however cost a bit more, we’re looking at S2 $1800 average, and S1 $260, so in order for S1 to get to 1TH/s would be a multiple of 5, so 5×260=$1300, but the S1 cost $1800 1th/s, so buying the s1 will save $500, so I guess it doesn’t matter which one you’re getting, just depend on spending power.