I'm using CCW (cupcakeworld) caramel at the mo'; this mellows with steeping (usually a couple of weeks) to give a better all-round flavour as it's a bit burnt tasting when freshly-mixed as a single flavour.
It is simply a flavour and doesn't add sweetness btw.
I don't really like it on it's own and use it as a mix ingredient, so where it's used with fruits it can be vaped with less steeping, but with biscuit/cake/dessert flaours will need a steep.
I subscribe to the try fresh, if you don't like it leave it a few days, try and see what you think, and again if you don't like it leave it a few days more - rinse and repeat until it tastes right
Don't forget to take notes so you can repeat good mixes and alter ones that need tweaking