The construction of MIR titles reminds me a lot of older Springer GTM and Grundlehren der Mathematischen Wissenschaften series titles. I have a number of Springer titles I've picked up over the years and the older printings were beautifully typeset and bound with very good paper. I try to find the older printings of Springer books when I can when chasing down a copy for my personal library.
Springer books were beautifully typeset until they started having authors do their own typesetting. That's one of the mixed blessings of LaTeX.
Even into the early 2000s, Springer would often make the first printing of a textbook sewn-bound, then subsequent printings were cheaply perfect-bound. I stopped buying new Springer books online around 2005, because I wanted to check the binding before buying.
Interesting, I must have lucked out quite often and got the first printing back in the mid to late 2000s since back then virtually all of my print Springer books I bought back then were sewn-bound.
