I agree on the questionable need to use upwards of 80W, or even >50W. I've vaped on a wide variety of devices: dozens of RDAs, RTAs (Frankentank Orchid/Kayfun my fave right now), got into gennys again over the last few months, bridgeless attys for testing my DIY juices, every metal tank Kanger made. I like the iPV3, but I really haven't had any need to exceed 50W, although I haven't been in a super sub-ohm phase for a while.
I go through phases in my vaping: I'll get burned out on huge clouds and settle in at .6-.8 ohms with mech mods. Still, I love to build coils every night and they need to be tested

. But I usually vape max VG, primarily DIY, and I find the .6-8 range (with variance for certain set-ups) to provide the most satisfying vape for my subjective tastes.
But yeah, so far, I've been a tiny bit angry at myself for buying the iPV3. I knew I wouldn't really need the putative 150W output, that it's mathematically impossible as well, and that a better-designed, better-manufactured device at a similar price-point would be available in a few months. But what the hell, I wanted the capacity and flexibility, particularly in the low range. So now I'm back to my pet project of building my own DNA30/40 box mod out of an old British toothpowder tin, and putting my 20 yrs of design experience to work by studying etching.
tl;dr: The iPV3's a good device, it works and I like it. But I believe the "150W!!" is mostly just marketing hype geared towards a very competitive, over-burdened industry that's developing at light speed. We all know that there will be phenomenally better devices available in 6 months. Scratch that-- this is the vaping industry, change that to 2 months. It's just too easy to make the kinds of relatively basic devices we're still using. That's both a wonderful thing and a dangerous thing.