Ryanair creates a great deal of fear for the current and would be future pilots of legacy and other european airlines. With a couple of exceptions (e.g. Easyjet, maybe Wizz) no one really seems to have an answer to their business model. Lufthansa, Air France and others have stated this publicly as their reason for needing to set up cheaper alternatives.
The obvious benefits with Ryanair are that they are likely to survive and continue growing. So your job security (insovency related) and opportunities for F/Os to become a captain are a given. The down side is that Ryanair's out and out Taylorist (think Ford conveyor belt) approach makes you a small cog in a very big wheel. It is not difficult to think of reasons to dislike them and their business practices. But unless you win the lottery and get taken on directly by a legacy carrier there are sadly a lot worse places to be.