GreenSmoke was my first entree into
vaping, back in 9/09. The cartos were also my first indication that PG was causing problems...many problems. Dry mouth, irritated throat, gastric issues after a while, etc. My understanding was GS was one of the first to add some VG to the carto liquid to get more vapor, but there was still plenty of PG present.
I started making my own VG juices, but I either didn't know enough to fill the cartos properly at the time, or those cartos do not lend themselves to refilling well. Plus the batteries were not keeping their charge well soon after getting the kit, and they died completely within about 3 weeks. So I went with a Joye 510 and my own VG juices, and all problems were solved.