Yes we were totally ripped off by Yoshi at BitMain so beware! After buying over a dozen S1's and setting up a S1 based mining infrastructure he sold us 3 S2's the week before the S3 came out - bought them from him directly and he never even mentioned the S3...

We paid 1800 per S2 or around 5400 for 3 THs

Had we known we could have got 15x S3's or around 7.5 THs for the same money we would have never purchased them

Anyway - our 3 x S2's are generating around 0.07 btc per day on BTC Guild so after hosting/energy costs will never ROI

Total Waste of Money, will never do business with those guys again...