I was hoping to use the Flybe flights to connect with KLM onward to Frankfurt or Stuttgart, but you can't book through flights- because there is no codeshare available to Dundee- but there is for Southampton and Inverness
So it looks like the claim of easy linking into a major European hub may not be quite accurate (along with 6 days a week service. According to the Flybe website, that is only available Spetember into October 2016).
The cost of separate bookings is high, so it looks like EDI, ABZ or GLA for the forseeable.
It's a great shame, it would have made for an easier trip.
I spoke to a friend of mine about who used the London City flights for trips they made to London, they said that Stansted was useless for going into central London in their view, and they would not use the flights.