I don't know if all of your questions have been answered yet but I do see most of the information I've come across already mentioned in comments to this post.
The only thing I've not seen mentioned in these comments is the 25% cut that Dtube takes of the payout, some of which is used to pay for file storage. The fact that there is a paid service hosting the files makes me question the decentralization of Dtube too, but I don't understand IPFS and how it works so my worries might be unfounded.
Here is where I've found most of my information about it. https://bitcointalk.org/index.php?topic=2080964.0
The main con in my eyes right now is the inability to embed Dtube videos in steemit posts requiring people to go off site to watch them. But that's coming from a consumer perspective as I don't yet make videos, I can't give a full rundown of problems creators might face, but as others have said there seem to be lag issues, file type issues and such.