What you can find with some mods temp control is that if you build too high for the SS wire gauge, (i.e. 26g 0.8 ohms!), the heat capacity is quite high (how long it takes to ramp up and cool down), which means the mod will struggle with temp control. When the coil hits the temperature, the mod cuts the wattage but the coil takes a while to cool and so the mod cuts the wattage too much, meaning the vape drops right off, and then the mod sees that and hits the power again, so you get an on-off kind of vape. The same can occur with certain mods if you have the wattage set too high.
With 26g SS316L i never go over 0.5 ohms, and keep the wattage at 30 watts.