Biggest thing I recall is the balance....not frequency response but volume was jumpy high-mids to lows. Just different than your typical greenback tone, pretty stiff. And greenbacks usually sound good right out of the box.
Scumback M75, Emi Private Jack, Green Beret, Reissue G12M are the only greenbacks I'de recommend in that order. Oh and the Legend GB12 would fall somewhere in there as well.
Yes Aiken was using these. Mostly due to the failure rate of the Chinese Greenbacks. I have one of these speakers. It has the greenback tone. They have more dope on then than a European cyclist, so they can take time to break in. Overall a decent speaker.