In all fairness STN I think is much better suited for this one, and the fact that it's a MAG airport I'm sure helps. As has been said a lot of the main holiday destinations from STN are under-served and in some cases only served now by Ryanair, so a bit of competition and more choice for customers is a much welcome addition.
LTN already has a much bigger leisure focused network with EZY, ZB a bigger TOM short-haul network and a bit of FR arguably on the popular sun routes that LS would want to serve.
It will be interesting to see if this leads to any future impact on EZY at SEN, ZB from LGW and LTN in particular and of course the TOM and MT networks out of STN... I'm guessing also a more immediate impact is that the Luton thread on here may go a bit quieter than usual for a few days
