you should get quite equivalent results with both Soave-Redlich-Kwong and Peng-Robinson equations of state.
There have been many discussions about which is the best model ,
I think it depends from the field of application,
some authors give criteria for selection,
for example for hydrocarbons with acentric factors < 0.3 Soave Redlich Kwong is suggested,
however this is true for standard alpha correlation, as said
with the extended version available in Prode Properties (with parameters regressed to fit vapor pressure , enthalpy and liquid density of pure components) you should get quite equivalent results.