First I must say that I'm not professional classical guitar player, so my impressions may not be useful for all of you who are more serious about this instrument.
But still, I do play it a lot, and I felt that with these strings my instrument sounded noticeably better than with the previous set. Carbon G string is not a marketing trick, it really helps with that usually dull sounding string.
Also, my guitar teacher, classically trained musician, noticed strings and asked me which ones I use, therefore it also must mean something since he liked them.