Interesting article about the ipod touch ta
Main reason I would prefer a Duet
The reciever is easier to mod than the SB3, theres more room in the case, it offers easier direct I2S compared to the SB3's left-justified I2S (I2S is better than SPDIF if used over a short distance) , its a lighter current load than the SB3 giving a wider range of PSU options.
Main thing that was putting me off with the Duet was quite a few negative posts regarding controller drop outs and lock ups