I bought these as an upgrade for my Stage Right 15 aka Tube 15 which used to have Celestion Seventy 80 speakers. My choice was between the Eminence Cannabis Rex and these Greenbacks but upon a few blind tests I concluded that I prefer the sound of the Greenbacks so ordered those. Installation was quite simple, a drop in replacement. I haven't broken them in fully since I only played a few hours so far but overall I think it is a notable improvement, they don't have the ear piercing highs that the Seventy 80 used to have and sound nice and full. I think my tube amp sound is now completely on point 👌