I vote for square! I bought a square mini in lambskin last summer, I don't think the quality is bad, and it doesn't feel any worse or better than the M/L I bought in the same color/leather/hardware (yes, exact bag, diff size).
As against older minis, possibly yes, i wouldn't know. But, there have lots of discussions on TPF of decreasing quality across all lines, not just minis.
Thanks for your input! I went to the Neiman Marcus at the Stanford shopping center today and a very nice SA showed me two patent rectangle minis, one in teal blue and one in light yellow. It looks quite obvious to me that the two sides for the yellow mini already run over the flap. I mean the width of the flap is less than the distance between the two sides. And the yellow mini is brand new, not a display. So I guess the quality does go down. I asked for caviar and also the square mini. She told me the square mini is hard to find now and so does the caviar..
I'm thinking of getting one in Europe... UK seems to have more minis in stock. Is that true?