Is there another Borodin thread this can be appended to?
Just became reaquainted with the SQs on EMI, and the first is most certainly the first major Russian SQ, Tchaikovsky notwithstanding. It's big and meaty and original and took Borodin about 10 years to complete, and the care shows. I have nothing really to add about No.2, except that its fame is more than justified (as opposed to the first, the second was written very quickly). I haven't heard Tchaikovsky for a long time (1-3+mvmt in Bb), but I would like to compare.
However, I just wanted to give these SQs their props. No.1 is really a masterpiece, mature, and comparable, IMHO, to Beethoven's late minor key SQs (probably the best SQ between 1826-1888?).