There are collectibles, dustables, play before you payers and simple "blue chip" horns. Bachs in my not so skimpy experience belong to group three and Yamaha to group four. Ambassadors are a very interesting case as I have played many and I considered them in their day to be no more or less than a good student horn. Today, they are also a good student horn -perhaps with the liability of being old and potentially worn. Certainly nothing that I would take on stage.
Clark does make a very good point however. I read it like this: many of the horn preferences stated here at TrumpetMaster have limited use to others because none of the really vital aspects of a horn are discussed. We have some basic stuff that applies to all horns: in tune, easy to play. Then we have characteristics that we have no adequate descriptions for: color and dynamics, articulation and projection, feedback and response. These hard to describe parameters require that we are familiar with the player claiming them. If the member only plays in a wind band, they have a specific use case where their opinion is useful to some others. That opinion would not necessarily help someone looking to play lead in a university jazz band or symphony orchestra however.
As this is an open internet forum, the chance of quantifying opinion is about zero. I have learned to consider the source and generally avoid commenting on "vintage" horns of any type other than recommending to play before you pay whenever possible. I have had 1 bad and 2 great Bachs, but even used the bad one professionally until it was replaced. I am not n+1 so every horn that I own is bought to be played. My measure is whether a horn adds color to the palette that I offer those who book me. That should give a frame of reference to any that read my "review" but for those that do not know where and what I play, much of what I write could seem like a rant. That would be a chance to ask a question, but being the open internet platform, often indignation is the response to critical. Valuable bits are lost before the thread gets back on track. Fortunately, the bits weigh nothing and as long as we understand their significance, we do have a chance to get back to the subject at hand without much collateral damage.