TFA sweetener is 5% sucralose and 5% ethyl maltol. It gunks your coils like nothing else, also it will mute the juice fairly quickly, even at 0.5%.
This is a two in one sweetener, ethyl maltol works great with other sweeteners but is a match in heaven if paired with sucralose. Sucralose sweetens the overall profile, while ethyl maltol only sweetens high and secondary notes. If a flavor contains already some kind of sweetener and most do, especially TFA then this sweetener will amplify the sweetness even more, hence some people believing that Tfa sweetener is more powerful than super sweet. It's not. If used, start with 0.15% and work your way up, but be mindful of other flavors that are used in the recipe, or you end up with a hot mess.
Ethyl maltol as explained above is only beneficial in combination with other sweeteners, otherwise only a specific or certain high/top notes are sweetened up, leading to that more subtle feeling you describing. In reality tho, it is the most underestimated additive and will not only gunk coils but reduces shelf life of the juice, as well as fading and muting out recipes. It's meant to take off harshness or edges in a juice not really for mouthfeel or wetness/juicyness some people try using it.
I never understood the use of 1% or more Tfa sweetener as well as ethyl maltol in private recipes, if you can accomplish the same sweetness or even more with other brands at much lower ratio. Ethyl maltol vs stevia or vs vinegar, which one is more artifical? I have no idea, but in general ethyl maltol for me personally would be the last choice.