The only things I know about the dna40 are this:
Temp control
1w to 40w range
Fires extremely low resistance (not even 100% sure what the ranges are)
Reverse battery protection
Larger circuit footprint with mounting rails which are user removable
Now available in large screen (pointless or useless for retrofit into a flask anyway, ok for a custom built if you want the larger screen)
Negatives:
Screen glitches
Several firmware updates/changes since launch. I've heard they've changed or added features on the latest versions from earlier versions. But, not 100% sure what those changes are. But as I understand it, there have been different releases of the same chip since launch (ie: small screen dna40) at least in firmware.
Now, my take on this is goes something like this.. If I wanted insane power (beyond my dna30 devices) there are other options (sigelie 150w?) out there. I generally vape in the 15w to 20w range as an average. Maybe that's because I know I can't go higher than 30w? i dunno. Can a person build to accommodate 40w 60w or 100w...sure. Would I? Again, I don't think so but I don't have that option available to me so it's hard to answer.
Is temp control for me? Another hard question to answer. It seems like a lot of hassle for protection I don't need. And I'm not clear if it actually improves a properly wicking build on a given wattage. I'd like to play with it, which is why I'll try the Chinese chip, I wanted the flask mainly for the enclosure anyways...not the chip.
Please, anyone feel free to correct me if I'm mistaken or misinformed. And I'll admit, I may not be thinking right about the dna40. I'm an Evolv fan boy, I'm saddened to hear reports of flaky dna40 chips/screens/performance. Which is exactly why I have not already jumped on the dna40 bandwagon, in my mind, the only reason to get it is for the temp control, I don't see myself needing the additional wattage power.
I hope that makes sense reading it, it did in my head