These CDs are blessed with stunningly clear sound, every strand of the music being audible as it's being played, and the Quatour Mosaiques perform with great technical ability. But, for me, the music very rarely takes flight. One of the reasons for this is the slow tempi that have been used for the allegro movements. For example, the allegro of the first movement of the Bb quartet K454 sometimes falters to the point of complete stasis, something which is common to nearly all the fast movements. Instead of flowing the music seems to lumber along from one beautifully played phrase to the next with little sense of purpose or forward momentum. The final movement of the Eb quartet K428 is plagued with a similar problem as the Mosaiques don't seem capable of discovering a true pulse for each work. A similar problem affects the often deeply expressive slow movements. There is just no 'thread' that goes through from the first bar to the last. As a consequence the music is completely drained of much of its life, vitality and power. I'm a big fan of Mozart played on period instruments, and the sound of these particular instruments is fantastic. It's just a shame that the interpretative qualities don't live up to the sonic qualities. Therefore I would recommend the Alban Berg recordings (on Teldec, NOT the EMI ones) of all Mozart's late quartets. These aren't without problems (for example they sometimes don't obey important repeats e.g. in the first movement of K499 or the polyphonic finale of K590) but overall they offer much more musical, enthralling and satisfactory interpretations.