I have to agree with openthewell because I use 24mg/ml tobacco flavor from JC, their Original flavor is very mild. I used a cartful of 36mg/ml tobacco flavor from Totally Wicked, also was mild but made me sick within about 10 minutes! so away with that, then I went back to the Johnson Creek 24/Tennesse Cured, and found that it had a "throat hit" for me, although it is mild also to some people, so I agree it is the flavoring, either PG or VG, doesn't seem to matter. So have now been mixing the Original tobacco with Tennessee Cured, (VG) still has a bit of "throat" to it but not as harsh. I don't really like a "throat hit", I guess!
And, I think it makes a difference from one model of e-cig to another. Have been using the Janty Stick with 801 atomizer, it is my favorite.