I used to work in NYC back in the early 80's so I visited some of these older stores. 47th St. Photo made me sick. Adorama was a hole in the wall place, but had a lot of interesting stuff. I really liked Olden - an old building with several floors and browsing was a lot of fun. Lens & Repro had a lot of stuff crammed into their space - I recall enlargers all over the place. I did visit the new B&H at some point - so it must have been in the 90's I guess. It was a very nice store and really customer-oriented.
As for the easel, I have a used Saunders 16x20. The blades are adjustable so I can alwaays keep the square. The other night I was using it and noticed that one of the blades wasn't square, a simple turn of a screwdriver and a square edge to align it with and all was well. This easel must be 15-20 years old and it still is going strong! I haven't tried the other brands, but I'm a big Saunders fan.