I don't drink the Koolaid any more and from what I understand, Mafell is at the very top when it comes to quality and just about every review of the Duo Doweller is very good.
I like dowels and I like to stay away from 'proprietary' consumables - like the domino tenons. Sure you can make your own tenons but dowels are pretty cheap to begin with. The Duo Doweler comes in metric but you can either buy metric size dowels or replace the drill bits with standard size
I have also read a number of reports of people breaking the domino cutter for whatever reason, AND a Domino requires a dust extractor to work properly
Festool 10 mm Tenons - $25 for 85! If I need to use floating tenons, I have the Leigh
Leigh FMT Pro Mortise and Tenon Jig
It seems when people buy a Domino, they start to go crazy trying to justify the purchase by using tenons in everything they do. (I have seen some real silly uses, but whatever)