Not surprised that a solution introduced so early would have issues.
When all the major tuners shy away from the platform, I'm skeptical when anyone can come out with something that claims to do what others can't. Perhaps Hartge has figured it out but we likely won't know until several of us take the dive and live with the tune for an extended period of time.
While Dinan is overpriced, I tend to think that they take the most care in "cracking the code" which ultimately leads the other tuners to take notice and then raise the bar. Like it or not, we should take cues from those companies that have been in the BMW game for a long time. Should Dinan offer a solution, I will then start to take notice. Not saying I will buy the Dinan tune but this will show me that someone with skin in the game, via its warranty, has figured out how to effectively manipulate the 535 F10 platform.
With all that having been said, if we wanted more TQ and HP, we should have opted for the 550i.