Twisted Noncommutative Field Theory: Wick-Voros vs Moyal
  We present a comparison of the noncommutative field theories built using two different star products: Moyal and Wick-Voros (or normally ordered). We compare the two theories in the context of the noncommutative geometry determined by a Drinfeld twist, and the comparison is made at the level of Green's functions and S-matrix. We find that while the Green's functions are different for the two theories, the S-matrix is the same in both cases, and is different from the commutative case. 
Salvatore Galluccio, Fedele Lizzi and Patrizia Vitale