As you may know, our DualMiner USB 2 (DM2) has a price promation on volume purchase this month. When you purchase 50+ DM2 devices, you pay $61.2 for each DM2 device. I did a quick cost/reward comparision between the DM2 and one GPU (Radeon HD7970) system, and reached a conclusion that the DM2 is alreay neck to neck with Radeon HD7970 when comparing cost/reward matrix. Below is my detail analysis;

Assumptions:
Difficulty is steady

Given Conditions:
Host required to mine is not included in this comparision
External cooling is not included in this comparision
$/LTC convertion rate = $16.94
Electricity cost (KW/Hour) = $0.15
Pool Fee = 2%
Duration for comparision = 375 days
Radeon HD7970 parameters; cost=$310, Hash Rate=700KH/s, Power comsumption=250W
10 DM2 parameters; cost=$612, Hash Rate=700KH/s, Power comsumption=15W
LTC reward calculator used in this analysis; https://bitcoinwisdom.com/litecoin/calculator

Calculations:
GPU extra electricity fee (/day) = ((250W-15W)*24/1000)*0.15=$0.846/day
GPU extra electricity fee (375 days) = $0.846*375=$317.25
10 DM2 $ reward from 375 days' mining = $743.9 (using calculator https://bitcoinwisdom.com/litecoin/calculator)

GPU net reward (at the 375th day) = $743.9-$310-$317.25=$116.65
DM2 net reward (at the 375th day) = $743.9-$612=$131.9

Takeaway point: With the per device price of $61.2, the DM2 should give you better long term ROI compared to Radeon HD7970.