Day before yesterday (my 1st day), I started out on 100% PG, and it was really hard on the back of my 
throat... coughing spasms, etc. 
So, yesterday, I did a 50/50 mix all day long, and it seemed better, but I'm still occasionally getting times when that bad harshness rolls back in for a while. 
I guess I'm trying to figure out if I have an intolerance for PG. 
Also, if I end up having to go with 100% VG, isn't that supposed to be really bad for the heating element?