So go with S3+ unless you know the S3 does preform well. If the S3 performs good you could go with it.
Correct. The first batch was awful and I may be wrong, but I remember submitting some info for a small refund instead of receiving discounts on future batches.
Anyway, S3+ was basically what the S3 was intended to be. All of the S3s we still have being hosted run pretty stable at around 441 GH/s. I don't think that the difference in performance is really worth the difference in the street price though. That's just my 0.0001BTC
It was very hit and miss on first batch. Some got lucky got a preforming one and a little refund. Others got a underpreforming one and little refund. I think my personal rate was about 50 percent, so pretty even of each. But I'm sure overall was decent percent as they did partial refund.
But if possible I would still avoid batch one. If your buying S3 ask for picture of it preforming. You can tell by speed if good machine.