In my opinion, you have have basically two choices in a regulated mod.
The MVP or the ProVari.
These two devices can't be any more different, but in my opinion, it's the only two choices to be had.
The MVP2 is your value move. It is probably the best bang for your buck. It's a great vape, has great features, and is capable of being a primary vape and quality backup vape. It's also easy and inexpensive to replace. And it's best part is that it's disposable. There is no expectation it will last. It's built well enough to last throughout it's battery life and that's it. You use it until it fails and you replace it. End of story.
The ProVari is your long term move. It has 4 years of proven design and performance. It is a quality built. It's more expensive by a factor of 4 but it will last. It may not have all the features of some of the newer mods, but it does what it does extremely well.
The other 33.3 hz mods are fine products but they dupe you into believing you have something that will last forever and you later find out you don't. At least the MVP doesn't set you up for disappointment. You know going in, it's going to fail eventually.
For the new generation of DNA based units, time will tell. There are many choices out there and they look to be high quality, but time will tell whether these units will pass the test of time.
People can complain about the ProVari being long in the tooth. I was one of them. But one thing about being long in the tooth....It's proven to last.
If I am looking for a year long investment, I'd go with an MVP. If I want something to last longer, it's a ProVari.