not trying to start a ruckus
but personally i prefer the leaves. i raised silkworms---normal and zebras all summer last year on nothing but leaves-------i had a system going that worked very well and it was fun. YES they eat an incredible amount of leaves, i had three separate trees that i collected from. i didn't, however, wash them at all------if they had rain water on them i would dry and that worked out fine. i am also an avid tree climber so...........
both will work.... if you start to feed the worms mulberry leaves they are VERY fussy about going back to chow..
also, i only have one dragon----i imagine it would get to be overwhelming (leaves) with few more than that.
good luck!