I'll support JFP on what he says.
I used to work for Jet2. Really enjoyed it. 5 good years. Not perfect, but very good. You could talk to the top man openly and honestly. I did often.
You won't get rich in a hurry but you will have stability. That level of security is a valuable asset.
As for the friendly aspect, well let me tell you this. To the pax, the crew really enjoy playing host and looking after the customers. Better than that, internally, the Staff are excellent at looking after one another. There really is a great family atmosphere. That is why it hurt so much when I left in 2009. Also why there are so many tears at Blackpool now as the airfield closes.
If I was taking a job in UK and had a choice of carrier to fly for it would be Jet2.