I had the 3's and moved up to the signatures. They look the same but I think the sigs are much better than the 3 in every aspect,although the 3 was very enjoyable in my opinion the sigs have a better high end and are more dynamic.I can't really comment on the 3a. Unfortunatly I must down size, my sigs are currently for sale. My comments are sincere not a sales pitch.
