Taking this winter as an example in some bases, I understand, it was a good deal and in others it was a bad deal. In the base I can comment on the people who went job share only got the same flying they would have got anyway. i.e. every other week 2 days flying 3 days stand by. So very little money. Lots of cars sold and credit cards pushed to the max. Also something worth considering is that as you work every other week you are going to spend an entire winter on earlies or lates if that is something that matters to you.
The system only works if you are going to get at least 4 of those days on. As with everything else Ryanair NOTHING is guaranteed ! So look carefully at your bases winter schedule when it comes out ! My advice to everyone planning to stay at Ryanair thorough next winter is budget for three months unpaid leave and then anything you get is a bonus.
Back on topic, if you can budget for three months off and you are unfortunate enough to have to commute to your base then it will definately improve your lifestyle for the winter and not hit you as hard in the pocket by the time commuting living costs are taken out.
In my opinion, for whatever that's worth, The deal will suit some and not suit others. Be careful study the schedule and budget accordingly. You don't really need those Audi TTs and Breightling watches. Enjoy more time with your friends and family instead.