FYI: these string have only been out since Nov 2014, many folks have posted in threads here, search for AQUILA LAVA to find them
IIRC, most of the reaction was 'meh'
Mimmo from Aquila said here on UU and in interviews that these strings were created in a darker color as a tribute to the peoples of Hawaii and that this color was intended to satisfy those who want the more traditional dark color, as black nylon strings have special significance to Hawaiian peoples (dont recall what that significance was exactly)...
I've tried the GCEA LAVA strings on tenor and baritone and while functional, on the 4 ukes I tested them on, they did not have a complex tone and lacked any meaningful sustain, and the only positives for me were that the intonation was ok, and that the strings were THINNER than regular Aquila Nylgut or SuperNylgut, and felt more like fluorocarbon strings under the fingers.
After having them on for 2 weeks, the 'C' strings sounded tubby and dead to me and I could not get them off fast enough.