@Stephen Howard has an interesting article on the 1959 Selmer Mark VI alto. I have not referenced it since it will show up in a search or simply going to his site. It is listed in his left column menu.
(Don't want to load up his site with unnecessary traffic. Bandwidth costs good money.)
He gives an interesting take from a technician's point of view. Mentions in some instances the Selmer Balanced Action was better. The VI is still well loved, a solid workhorse especially after servicing to fix its faults and shortcomings. Like many saxes, a simple change in mouthpiece can produced the desired characteristics.
Perhaps the best concluding statement is Stephen's,
"Bear in mind too that there's some truth in the modern-day saying "No-one sells a good Selmer". I mean, if you had one, would you??"
I only have experience with a limited amount of makes and models of saxophones, so cannot comment except for those I have.
My 1952ish ("ish" because there are gaps in serial number records and mine is between two years) Le Blanc Model 37 Beaugnier Vito low-Bb bari, after I restored it, plays beautifully in tune and it is very easy to play in the altissimo register. It lacks the "France" stamp near its serial number, so I gather the possibility that then as a factory under the LeBlanc Corporation, parts or partial assembly and parts were shipped off to Kenosha, Wisconsin? and final assembly done there.
It was a joy to play as my last experience with a bari sax was in the latter 1980's, when I played a King low Bb bari sax for the 300th Army Band, Bell, CA. I did a few minor repairs to restore it to playing condition. It played very well in tune. I could play it mildly or put out that fat bari sound in its lower register.
I bought the 37 as an eBay project sax in 2010 for $315 total. Taught me a lot about adjustments and dent work. It was a former high school loaner instrument that saw its better days with many repairs.
Last year I was so glad to obtain a very low usage 1952 Le Blanc Model 37 Beaugnier Vito alto saxophone. It had a high serial number, gather probably continued production into early 1960's. Tarpley Music replaced 5 pads plus new neck cork and a few other tweaks. It is a wide body sax, used a tenor end plug to protect the neck octave key mechanism. Bell rim diameter is that of a modern tenor sax. Buy + servicing + new case about $550.
It has the earlier 1940's left pinky table like my bari. Properly adjusted these play like professional model saxes. For a pensioner should do me well until I attain my 'last call'.