Both AIO's and Mods provide refillable or replaceable tanks, and as such we can control the contents of our e liquid, reducing or eliminating cancer-causing carcinogens found in tobacco cigarettes. Be aware that pharmaceutical grade nicotine is not carcinogenic, besides, most of the harm stems from combustion, which is not present with vaping.
The majority of today's e Cigs offer longer life batteries, an array of safety features, and the ability to adjust and fine tune voltage and wattage. This does not apply to most AIO styles as the power output is governed solely by the Coil, or Atomiser. All starter e Cig tanks utilise easy screw in replaceable Coils.
Many of today's beginner devices, such as the AIO's, have only a single fire button yet, are sufficiently powerful to assist with transitioning from smoking.