Could anyone argue that the six string quartets of Paul Hindemith are on the same level as the six quartets of Bartók or the five quartets of Schoenberg or the 15 quartets of Shostakovich? Probably not: there have been very few recordings of Hindemith's quartets and most of them were made by less than first-rate ensembles, so there is little evidence to mount an argument for the work's outstanding qualities.
Does the Kocian Quartet make the case for Hindemith's quartets in its 1995 recording of the complete cycle? Yes, but only up to a point. The Kocian is a more than adequate ensemble with a rich if sometimes ragged tone and a powerful if occasionally erratic sense of rhythm and it is almost but not quite up to the challenge of Hindemith's quartets. One can appreciate the intellectual effort and the incredible energy the composer put into the works, but one can only dimly apprehend the wit, depth, and strength of the works. If there were also recordings of Hindemith's quartets by, say, the Alban Berg Quartet, to make the argument for the work's outstanding qualities, the Kocian's recordings would be decidedly second-rate. But as things stand, the Kocian's merely acceptable recordings are as good as it gets. Praga's sound is a bit hard and a tad harsh.