If you race then Kevlar, if you day sail then Kevlar, if you enjoy sailing and the look and feel of a properly trimmed sail then Kevlar. they will last longer and they will hold there shape longer. the new materials they are using today are way better then when they first started making laminated sails. Delams are not happing if you take care of the sails and keep them stored out of the sun. Kevlar cost only a little more as the labor is less to make the sail. and they don't really make many with real Kevlar any more but they use other types of arimids that look like kevlar but work even better. as for weight yes there is a big differance, the first time you pick up the bag you will notice.
"FULL TILT" SOVEREL 33
"GOLD RUSH" PRINDLE 16