Written straight after his Ninth Symphony, it's his 'American' quartet, and most popular by far, and with excellent tunes it's no wonder.
Listening to this today, the first two movements were rapt and heavenly, i suppose the second movement Lento really got to me, a wonderful experience, to me it seems that it's a sad lament, a dour yet uplifting tune!, one continuous cantilena that changes shape here and there, the first violin plays the main tune [0:00-0:54], full of pathos, and the cello takes up a darker version of the tune [0:54-1:38], and then they go into a brighter counter melody [1:39-2:41], with a nice gush at [2:00], even the viola gets it's solo chance to play this counter melody [3:47+], there's a nice long passage for the violins playing the main tune [5:22-6:59], while the viola and cello bow/pluck the rhythm, the piece ends with the cello bringing us back to the main theme [7:00+] and descending down into the bass, and the viola having the last voice [8:07-8:129], like i said the whole thing is sad, and yet so uplifting at the same time, Dvorak singing the blues!.
Here's the second movement being played on YouTube.