I know what you mean... I tend to notice around 3.9 to 4.0.Yes I do. I use it in the hammer with vtc4s or in the king v2 with LG HE4s. As long as I dont drop below 4V it vapes really clean but if I forget to check and drop below i can feel the difference almost immediately.
I use 26650s, so I wonder if I don't notice right at 4.0, because it's a more gradual drop...being a 3500 mah...weird.
That tank on the Hammer looks a beast.
I have mine on an Ehpro Seeker, and when I put that next to my V1 on the Copper Vanilla mod...the thing looks like it's parent...