How old is networkmanager now? Connman is barely out of beta stage and Dan is shooting with long range missiles at it. Frankly, it sounds like he is "scared" of connman to me :)
The fact that Marcel hasn't gotten to writing decent powerpoint presentations and documentation yet (arguably) is not a sign of that connman is evil or in any way mature.
Dan's Blog post is also skewing the comparison by neatly formatting the strong points of NetworkManager, and then making the connman points a homogenous blob of text.
It seems Dan is blog/ranting more against the PPT presentation itself than connman. And (ab)using the same tactics as the one applied in that very PPT: misinformation.
Again, I'd like to see a technical comparison based on facts, not one based on either side's propagande.