I am sure DY has a good product at the moment but never the less it is known that DY compared to FR and EZY is the one with the least capital in hand and some claim there are some serious problems ahead for DY and their cash-flow.
I have never flown with them (yet) and I keep hearing of their free wifi and the non existing (in flight) high sale pressure technique by the cabin crew. It is worth however having a look at the fuel price that has dropped some +6% in the last 12 months and now DY has just announced a need to increase baggage and allocated seat selection by 33%.
Unlike what many on this thread believe DY is not considered a big threat by EZY. Not yet anyway? The main threat for EZY is Vuelling owned by IAG and we may in the future see BA short haul LGW being replaced by Vuelling planes and a base on very bad terms and conditions making it very competitive against EZY and that includes DY as well if they are still based in LGW by that time.
Regarding wifi it is believed that it will be on all EZY planes by 2017.
I wish DY all the best but I seriously think they have got too many balls up in the air trying to compete against everybody and it can easily be the end of them no matter how many planes they have got on order.