The disadvantage of using Bitfury chips is the low "GH density". PCB size = 12cm x 12cm ? If boards are spaced 1cm apart = 144cm3. 42 GH per board. 0.29 GH/cm3 or 3.4 CC/GH. Fluorinert runs about $0.80 per CC ($80 per Liter), thus at 3.4 CC of fluid per GH the fluid cost is $2.72 per GH which is pretty high. The higher the GH density the less fluid needed per unit of hashpower and the more economical the system. My goal would be to get fluid costs to <$0.25 per GH and full system cost (excluding SHA-2 boards) <$0.50 per GH.
So it's really not the chip but rather the PCB design that is "low GH density". If we could redesign the PCB, it may achieve a much higher density and much smaller volume?
Well the low GH value of the chip contributes to the low GH density. Note this isn't to say it wouldn't work. It certainly would it would just mean using more immersion fluid per GH/s. With the high cost of Fluorinert that means a higher cost per Gigahash cooled. Still to be clear it will work fine it just will be less economical.