As Bitcoin mining gets ever-more competitive, energy efficiency has become just as important as price. Accordingly, I took note of the Antminer S3 miners being offered at ZoomHash. They're 453 GH/s miners that use just 355 watts of power at the wall. In comparison, the S1 units I reviewed in March do 180 GH/s at 360 watts. At $349 for the S3 (on sale for pre-order), that makes them one of the most energy-efficient miners on the market, especially at that price. The 800 GH/s to 1 TH/s devices on the market typically need 800-1000 watts of power. That said, this is a pre-order price. They ship on September 20th from Hong Kong, and they'll take 3-4 business days to arrive in the U.S. (check for details on your location)—waiting a month will have an affect on your ROI, and mining is always a gamble. To help even that gamble, ZoomHash set up a 5 percent coupon for our readers (coupon code MacObserver). Just enter that coupon during the checkout process. I'll be posting a review once I receive my units.