I've had great luck with my rDNA 40, got it in January 2015 and I still use it. I know a lot of people reported problems early on, but this is one of the most reliable mods i've owned. Even the coating on mine is still pretty much intact, I'm sure using the silicone skin helps tremendously.
If they do decide to release a DNA 75 mod, i'd like it to be in 26650 form, and as small as they can make it.