I really don't understand what jjm is driving at as regards PRSI and pensions...
The way I look at it, leaving pre-1995 public servants aside, everyone who is paying Class A (and their employer!) is paying the same proportion of their income in PRSI in order to obtain the benefits it provides, one of which is the State pension. This is regardless of what sector they work in or indeed the level of their earnings, so the CEO gets the same state pension as the cleaner who earns a tiny fraction of their salary.
Separate from that, the public sector employee pays a pension contribution (and into the future the PRD is being converted to a further pension contribution) towards their defined benefit pension. The benefit they actually obtain in the future for these payments will depend on the level of the state pension when they retire.
The way I look at it in relation to my own situation is that I could at some point, take a private sector job which would pay me a higher total remuneration (including benefits like bonus, employer pension contributions and healthcare that the public sector don't offer). But there is a trade off, and as part of evaluating the two sides of the scale I factor in things like the security of my job and the value of the defined benefit pension, against the increased take home pay from the private sector.
People grinding their axe about "gold plated" public sector pensions, and using the example of someone retiring with a pension of say €50k+, tend to conveniently overlook the various reports on public sector pay that find people at senior management levels are actually substantially lower paid relative to their private sector equivalents and the gold plated pension is one of the main reasons why many of those people remain in the public sector.
Including the PRD I think I'm paying around 13% of my gross pay towards pension, and I'm fully aware that this is not the economic or actuarial cost of the benefits I'll accrue. The difference (the amount that my employer is going to cover), in my tallying up of things, broadly equates to their contribution to my pension, no different than in most large private sector organisations DC schemes where employers will match or exceed the employee's contributions.