Originally tried to post this yesterday but the website went down just as I pressed the fire button - but this is more a comment on the business perspective rather than the marketing side:
You'll get as many opinions as there are posters. However, from an aviation industry point of view:
Ryanair, easyJet and the probably Air Berlin but possibly germanwings. Why? Financial stability, access to cash, profitability. In short, value. That's not to say they're the best to work for!
What they have right:
1) easyJet operate a frequency based model - good for attracting higher yield business class pax on trips from and to the larger cities. Smaller aircraft size gives good frequency - so unit size is right for their model. They fly to the right airports! Not miles from city centres. Good strategy, well applied.
2) They've got turnround times down to excellent minima. That means they can get extra utilisation out of their aircraft, so the productivity of the crews and the aircraft is excellent - way better than a legacy carrier. Great way to get costs out of the system.
3) Good yield management system that is very adaptive to market conditions and ensures that overbooking is minimised (eliminated is perhaps going a bit far!).
A very smart thing is that you won't find them competing with Ryanair directly on any routes other than those inherited from Go. easy know that their cost base is very low, but that Ryanair have a cost base that is lower. That means that Ryanair can always beat them...
I've got to fly so I'll let everyone else have a turn - I'm sure there are others who disagree with my opinion and there are those who will certainly want to give you the reasons they think easyJet has it all wrong!