I found 15% didn't cut it at all but 20% pretty good. It's one of those flavours that seems to fade the more you vape it, though, I found. Wouldn't buy again.
Same here 15% was almost tasteless moved it up to 20% still tasteless threw it in the steeping draw for 3 weeks and it did get better but I could still only vape it 20ml at a time or the flavour would just die it's not a adv in my opinion
Part of the real joy with Mixology is that you can adapt the one-shots to suit your own taste. I don't vape any of the T-juice range on their own, always tweak them with other flavourings. JTR is not a favourite of mine, I don't really go for creams but when I tried JTR I had to add more Raspberry to get the fruitiness I wanted. Mixed at 20% T-juice concentrates become pretty expensive.
I use it at 20% in a 50/50 mix and find it to be prettu strong. Agree wit @scrumpox tho' it helps to add a little of something extra to make the flavour jump out.