I bought a Z Unlackered Z
Also onwed a Z lackered tenor a few years back!
As for sound,in my opinion,no difference!
I prefer the alto way better then the tenor,and again only my opinion,which some wont agree!
As far as the finish,it does nt matter to me,shiny or a old lookin saxe after about a year and a half,but be prepared that it ages very fast,and darl spot here which are not the nices thing on a horn!
If you take it with a finish,then much easier to keep it in beautifull looking look,If you want that!

Best of luck in your choice!
My best regards
Saxobari