The Reference 54's construction is simply stunning. Every little detail is perfect. The engraving is lovely, the key posts are perfect, the key fit is perfect, the lacquer is unique, and the neck to body fit is beyond a doubt as good as it gets. The key height is set a little higher that I have seen on other Reference 54s but the sound is huge (and perfectly in tune). The key pop (action) is good (but not equal to or better than my 82Z). The f# trill pearl is gorgeous, and the high f# key has an appearance that makes the 82Z's bar almost laughable. I also like the front f pearl--cosmetically--it's a nice touch.
Quite frankly, the horn is perfectly constructed and as cosmetically perfect as any horn I have seen and felt. It has the beauty and construction of a Patek Philippe with the accuracy of an atomic clock. This Reference 54 alto is truly a scientifically perfected work of art.
The 82Z is a very well-built instrument, but its construction is not "stunning." It kind of reminds me of a Seiko--perfect timing (playing) but not truly customized. The 82Z's engraving is nice, but it lacks the fine detail of the Ref. 54. The key fit is good, but it does require medium viscosity key oil to get/keep some of the rattles out (but I do play the heck out of it). I had its key height custom set--its sound is huge and it's perfectly in tune (well, you'll see). The neck to body fit is good, but this Ref. 54's fit tenon fit is simply perfect. The low c# key responds great (now that it has a "leaf spring"). Yamaha 82Zs are very consistent and well-made saxophones, but they lack the splendor of the Selmer Ref. 54 (opinion).
This horn was simply amazing--I still hear this thing. It had a full voice and a flexible and resonant sound. Moreover, its intonation was simply as close to perfect as it gets. It was not as brilliant and free-blowing as my Z, but it did have a fuller/richer sound. I felt the Ref. 54 was a little too resistant--a different neck on this horn (or an opened neck pipe) would be nice. But the resistance may yield slightly more solid upper note stability; it is definitely more centered than my Z, more easily controllable, and I think the intonation required less effort to stabilize as a result. The ergonomics were very comfortable, and the left-hand spatula keys were more comfortable than my Z. I did not like the right-hand side keys as much as the Z, and I'm not sure how I would adjust for that. The left-hand palm keys, on the other hand (no pun intended) were very comfortable. This horn, to my ears, had the profound color of the SA 80 II with the flexibility of a great Mark VI and the intonation of the Series II. But I was not overly fond of the key action on the horn. The springs on the Ref. 54 are possibly shorter than those on my 82Z. (I dislike the same thing about the 875EX--the springs are shorter and the action is less "poppy"). The Reference 54 is an amazing player with a full voice, a robust sound, and great intonation.
The Yamaha 82Z, in terms of playability and sound, is an equal to the Ref. 54--it is just different. After playing the Ref. 54 for a few hours, I switched back to the Z and noticed a few intonation glitches above high-b that I have been apparently adjusting for since switching to the Yamaha 875EX several years ago (and then the 82Z). I think this may be due to the free-blowing nature of the G1 neck. But it only took about ten seconds to readjust and stabilize the intonation. Still, the 82Z is the most free-blowing, flexible, "brilliantly rich" and resonant sounding saxophone I have played. I like the key action on the 82Z significantly better than on that Ref. 54. The Ref. 54 simply lacked the pop of the 82Z's action, which I attribute to the spring length (I could be wrong). If I found a willing repair tech, I would have a custom f# trill key built for my 82Z with a pearl instead of the yellow brass key. (If you're out there and willing, please PM me). I still really like my 82ZUL. Moreover, I prefer the key action on the 82Z--it truly pops.
I really think both Selmer and Yamaha have hit the spot. These two altos are a lot of fun.