Every IR maker (like every musician) believes their work contributes something unique, and in fact they do. Different makers' IRs of the same speaker in the same cab with the same mics no doubt sound different, because of the countless variables involved, between the specific speaker, cab, mic, mic position, room, position of the cab in the room, humidity, temperature, yadda.
Your mission, should you choose to accept it, is to figure out what you like! Good luck with that!