Also, later (quoted in the chapter '1879-1881'), "I wrote that music (Vakula) with affection and with delight, just as I did... the Second Quartet" (from letter to Nadezhda von Meck, ibid).
From reference [3] (page 83): ‘The Quartet Op 22 was played by F. Laub, I. Grjymali, V. Fitzenhagen, and Y.-G. Gerber, at A. Rubinstein’s house.
At the rehearsal Davydov said it was Tchaikovsky’s best work; Auer said that it had the force of Beethoven (according to Modest the only composer many Russians would listen to); Malozemova wanted to send a congratulatory telegram.
Modest heard Rimsky-Korsakov unreservedly praising the work to Cui, as also the Grand Duke Konstantin Nikolaievich to whom it was dedicated, and Count Litke.’ Tchaikovsky replied to Modest in a letter (29 October 1874): "I am glad that you, Malozemova and all those who sympathise, liked my quartet; I regard it as my best composition; none of my works flowed out of me so simply and easily.
I wrote it practically at one go and was astonished that the public did not like it, for I find that compositions written spontaneously have every chance of success."