This is all very strange but demonstrates the subjectivity of this topic.
I love all strawberry juices and have around 15 variants - TFA Strawberry Ripe being one of my favourites
@eightbitraptor.
When I discovered Apple Fuji I put it in almost everything for a while and got through 50ml in 3 months
@Tazz.
As for melon
@geordie12, I've found every one overpowering, even in minute quantities.
What I've discovered is that those flavours that are very weak usually improve with steeping.
On a side note, the worst flavouring I've ever used is INW Sesame Sweets, which tastes like vomit and I had to throw away because even in a sealed bottle it was stinking the room out.