After using both APV and mech mods for some time, if you ask me to choose only one, i would go for the APV. APV give you functions like checking battery voltage, check resistance. Option for you to bump the voltage/wattage up to your personal preference. The biggest reason would be for checking battery life, i wouldn't want to overuse the battery that it will ruin or shorten its lifespan. On an APV i can check time to time and know when it is time for recharging my batteries.
Thats quite true. There are controls or monitoring features for a APV as compared to a mechanical mod, not sure if there is a window to check on the gas levels on some or the popular mechanical mods. But other than that, i would say mechanical mods are kinda pretty easy to maintained and would last long than APVs. Would like to get my hands on both APVs and mechanical mods to try for a personal feel myself