I also have a tranny that is like a 6m. I owned a 6m and the tranny at the same time. Both were great horns. The tranny to me was a little darker and fit my concept so I sold the 6m. I bet you could find two of the ladder horns with the situation reversed. Each horn is going to be different. Find what you like.
As a side note: I've owned and for a time a Ref54 alto and a Z alto. The only other horn I would have considered keeping over the tranny is a Yamaha 875EX that I played at a store once. These are really different horns. My advice is just find a horn you like no matter what it is.