slim_slag: I think ryanair's passenger numbers speak for themselves.
To an extent. RYR's big selling point is that they're cheap - but we know that they're not always the cheap
est for a particular flight on a particular day etc. There'll be a proportion of RYR pax who book because they think it must be cheaper than with others; after all, everyone says so therefore it must be true. But it's not always the case.
This isn't a RYR-only phenomenon: The same thing happens for EZY and SWA amongst others. In a sense, this is a opacity benefit that accrues to these airlines from not participating in competitive pricing GDSs.
As for the experience, you basically get what it says on the tin. When it all goes right, which is most times, it's fine. When it doesn't,
it can be bad. Whether you can live with those risks is a matter of personal choice.