Basically, every mod has a power board which is going to take "juice" from your battery and turn it into wattage. Boards vary wildly in how efficiently and well they do this. So yes, mods can vary quite a bit in performance if using the same "wattage" across the board. For example, my Steampunk nanos have a very efficient board, which means when I use them, I am often using "less" wattage and get excellent battery life due to the efficiency of the conversion. It can be quite noticeable, the external battery Pico for example seems to perform with much less efficiency than some other mods. I have an Eleaf Invoke which to my understanding uses the same or similar board, and I do vape it at slightly higher wattages than some of my other mods, to achieve more or less the same "effect" etc. I'd say there could be mod to same mod differences due to the manufacturing process.
Equally, coils can have variances, which is another reason the priming process can be useful.... As you wind up finding your "happy place" as you prime one coil vs another. You may find some coils vape best a few watts higher. And as the coil life heads toward lack of useful life, it will often mute and/or provide less vapor, leading many people to turn up the resistance a bit before it dies, as the coil materials are degrading and not wicking and providing vapor efficiently. I'm not saying you should do that, but I've gotten to the point when I can pretty much tell if a coil is nearing the end of its useful life, due to less vapor production, or more uneven vapor production, and I don't tend to fill my tank up to the tippy top once I get there, as I know "burnt" which typically includes all eliquid once that happens, is just a few puffs away, so I keep my tank level lower until it dies.
Anna