I have also been listening to some of the Mozart string quartets -
Hagen Quartet, "Mozart - the String Quartets" on Deutsche Grammaphon from 2003:
I have been listening to Beethoven early quartets, and I wanted a little more context on earlier string quartets - these certainly "feel" different to me from Beethoven.
Also have done some reading about string quartets in general. It seems like string quartets have been the "people's" form of classical music, and that the sale of sheet music for string quartets was important to composers, reaching amateur musicians who were playing the music. It also seems like the later Beethoven quartets may have been more difficult for interested amateurs to perform (though based on the internet, it looks like there are some accomplished amateurs continuing to this day working on playing this music.
I keep trying to think of amateur quartets playing quartets in the time of Mozart as the equivalent to a "garage band" today, but I am not sure that analogy quite works! Joking aside, actually working through a quarter by playing it seems like an incredible way to know this music.